CVE-2026-90179

UNRATEDCVSS · not yet scoredTrending — 3 sources updated this week
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EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS v2: —Exploit: None knownExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

In the Linux kernel, the following vulnerability has been resolved:

apparmor: fix deadlock in complain-mode change_hat

The use of change_hat when in complain mode can cause a deadlock when the hat doesn't exist and a new learning profile is created for the missing profile. This is because change_hat() has taken the lock to search the hat list and creating the new learning profile needs to take the lock to add it to the list.

From the bug report:

Originally found in 7.0.0 in LTS ubuntu 26.04 with pam_apparmor + su in complain mode set to change hats. Then verified in newest available vanilla kernel I've compiled to see if still present:

7.2-rc7 vanilla -> affected

checked also some other kernels: 6.18.44 vanilla -> affected 6.12.95 with debian patches -> unaffected

On systems without bug (for example 6.12.95 debian) it just prints:

aa_change_hat rc=0

On systems with bug, the executable always hangs, prints nothing and becomes unkillable. (And once stuck this way, it will cause any further hat changes to also cause the changing process to get stuck)

Then in syslog you can find hint about cause:

kernel: INFO: task hat:3409 blocked for more than 483 seconds. kernel: Not tainted 7.2.0-rc7 #1 kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: task:hat state:D stack:0 pid:3409 tgid:3409 ppid:2605 task_flags:0x400000 flags:0x00080800 kernel: Call Trace: kernel: kernel: __schedule+0x48f/0xfe0 kernel: schedule+0x27/0xa0 kernel: schedule_preempt_disabled+0x15/0x30 kernel: __mutex_lock.constprop.0+0x569/0xa10 kernel: aa_new_learning_profile+0x15f/0x210 kernel: build_change_hat+0x19f/0x3b0 kernel: change_hat.isra.0+0x5dd/0xd60 kernel: aa_change_hat+0x2f3/0x710 kernel: aa_setprocattr_changehat+0x121/0x1f0 kernel: do_setattr+0x28c/0x340 kernel: apparmor_setselfattr+0x20/0x50 kernel: security_setselfattr+0xf6/0x110 kernel: __x64_sys_lsm_set_self_attr+0x53/0x90 kernel: do_syscall_64+0xdd/0x5e0 kernel: ? __mod_memcg_lruvec_state+0xfd/0x260 kernel: ? lruvec_stat_mod_folio+0x8d/0xd0 kernel: ? __folio_mod_stat+0x2d/0x90 kernel: ? map_anon_folio_pte_nopf+0xd1/0x1f0 kernel: ? do_anonymous_page+0x184/0xa10 kernel: ? __handle_mm_fault+0x805/0x870 kernel: ? count_memcg_events+0xef/0x230 kernel: ? handle_mm_fault+0x1f0/0x2f0 kernel: ? do_user_addr_fault+0x2bb/0x7b0 kernel: ? do_syscall_64+0x94/0x5e0 kernel: ? exc_page_fault+0x75/0x160 kernel: entry_SYSCALL_64_after_hwframe+0x76/0x7e kernel: RIP: 0033:0x7f815e134c8d kernel: RSP: 002b:00007fff6df94ea8 EFLAGS: 00000246 ORIG_RAX: 00000000000001cc kernel: RAX: ffffffffffffffda RBX: 0000556d8c81d040 RCX: 00007f815e134c8d kernel: RDX: 0000000000000046 RSI: 0000556d8c81d040 RDI: 0000000000000064 kernel: RBP: 00007fff6df94ef0 R08: 00007f815e212ac8 R09: 000000000000000c kernel: R10: 0000000000000000 R11: 0000000000000246 R12: 0000556d8c81d010 kernel: R13: 0000000000000026 R14: 0000000000000046 R15: 0000000000000064 kernel: kernel: INFO: task hat:3409 is blocked on a mutex likely owned by task hat:3409.

To fix the issue, lift the locking out of the core of aa_new_learning_profile(), introduce a wrapper function that takes the lock where needed, and have build_change_hat() call the core function that no longer takes the lock.

In addition fix 4 other issues introduced by commit 32e92764d6f8d ("apparmor: grab ns lock and refresh when looking up changehat child profiles")

  • aa_get_profile_rcu() was replaced-by: aa_get_profile without the
accompanying rcu_dereference_protected()
  • an extra aa_get_label(label) was introduced at the start of
change_hat() without an accompanying aa_put_label() causing a reference count leak.
  • a reference count leak was introduced in the label_is_stale(label)
case, where the newest profile would be leaked instead of the label passed to the function.
  • a potential UAF when the lookup walks up the tree with new_ns != ns
the new label refere ---truncated---

CVSS v3
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EchelonGraph score
Not yet assessedNo source has published severity data for this CVE yet — no CVSS score from NVD or a CNA, no GitHub advisory, and it is not in CISA KEV. This is not a rating of zero; we cannot assess it yet.
EG Score
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EG Risk
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EPSS PROB
0.2%
EPSS %ILE
9th
KEV
Not listed

Published

September 17, 2026

Last Modified

September 17, 2026

References (3)

Vendor Advisories for CVE-2026-90179(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 7.2~rc7-1~exp1 (358 versions)
  • every version on: no fix on record
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Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (181 versions)
  • every version on: no fix on record
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Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (178 versions)
  • every version up to 7.2.6-1: fixed in 7.2.6-1
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Data Freshness Timeline

(refreshed 9× in last 7d / 24× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-04 23:22 UTCEPSS rescore
  2. 2026-10-04 16:20 UTCGHSA enrichment
  3. 2026-10-01 20:34 UTCGHSA enrichment
  4. 2026-10-01 19:51 UTCEPSS rescore
  5. 2026-09-30 15:04 UTCEPSS rescore
  6. 2026-09-29 00:49 UTCEG score recompute
  7. 2026-09-29 00:49 UTCGHSA enrichment
  8. 2026-09-28 13:52 UTCEPSS rescore
  9. 2026-09-28 13:52 UTCEPSS rescore
  10. 2026-09-27 13:49 UTCEPSS rescore
  11. 2026-09-26 15:59 UTCEPSS rescore
  12. 2026-09-26 05:05 UTCGHSA enrichment
  13. 2026-09-24 14:04 UTCEPSS rescore
  14. 2026-09-23 17:54 UTCEPSS rescore
  15. 2026-09-23 09:20 UTCGHSA enrichment
  16. 2026-09-22 16:01 UTCEPSS rescore
  17. 2026-09-21 21:09 UTCEPSS rescore
  18. 2026-09-20 20:16 UTCEPSS rescore
  19. 2026-09-20 13:35 UTCEG score recompute
  20. 2026-09-20 13:35 UTCGHSA enrichment
  21. 2026-09-18 19:28 UTCEPSS rescore
  22. 2026-09-17 17:23 UTCNVD update
  23. 2026-09-17 16:42 UTCEG score recompute
  24. 2026-09-17 16:19 UTCMITRE cvelistV5first tracked

Frequently asked(4)

What is CVE-2026-90179?
CVE-2026-90179 is a publicly disclosed vulnerability published on September 17, 2026. In the Linux kernel, the following vulnerability has been resolved: apparmor: fix deadlock in complain-mode change_hat The use of change_hat when in complain mode can cause a deadlock when the hat doesn't exist and a new learning profile is created for the missing profile. This is because…
When was CVE-2026-90179 disclosed?
CVE-2026-90179 was first published on September 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-90179 actively exploited?
CVE-2026-90179 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (9th percentile of EPSS-scored CVEs).
How do I remediate CVE-2026-90179?
No fix for CVE-2026-90179 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-90179 are linked in the Vendor Advisories panel on this page.

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