CVE-2026-31551

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-04-24. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

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

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

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable.

syzbot reported static_branch_dec() underflow in aql_enable_write(). [0]

The problem is that aql_enable_write() does not serialise concurrent write()s to the debugfs.

aql_enable_write() checks static_key_false(&aql_disable.key) and later calls static_branch_inc() or static_branch_dec(), but the state may change between the two calls.

aql_disable does not need to track inc/dec.

Let's use static_branch_enable() and static_branch_disable().

[0]: val == 0 WARNING: kernel/jump_label.c:311 at __static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311, CPU#0: syz.1.3155/20288 Modules linked in: CPU: 0 UID: 0 PID: 20288 Comm: syz.1.3155 Tainted: G U L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:__static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311 Code: f2 c9 ff 5b 5d c3 cc cc cc cc e8 54 f2 c9 ff 48 89 df e8 ac f9 ff ff eb ad e8 45 f2 c9 ff 90 0f 0b 90 eb a2 e8 3a f2 c9 ff 90 <0f> 0b 90 eb 97 48 89 df e8 5c 4b 33 00 e9 36 ff ff ff 0f 1f 80 00 RSP: 0018:ffffc9000b9f7c10 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffffffff9b3e5d40 RCX: ffffffff823c57b4 RDX: ffff8880285a0000 RSI: ffffffff823c5846 RDI: ffff8880285a0000 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000000a R13: 1ffff9200173ef88 R14: 0000000000000001 R15: ffffc9000b9f7e98 FS: 00007f530dd726c0(0000) GS:ffff8881245e3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001140 CR3: 000000007cc4a000 CR4: 00000000003526f0 Call Trace: __static_key_slow_dec_cpuslocked kernel/jump_label.c:297 [inline] __static_key_slow_dec kernel/jump_label.c:321 [inline] static_key_slow_dec+0x7c/0xc0 kernel/jump_label.c:336 aql_enable_write+0x2b2/0x310 net/mac80211/debugfs.c:343 short_proxy_write+0x133/0x1a0 fs/debugfs/file.c:383 vfs_write+0x2aa/0x1070 fs/read_write.c:684 ksys_pwrite64 fs/read_write.c:793 [inline] __do_sys_pwrite64 fs/read_write.c:801 [inline] __se_sys_pwrite64 fs/read_write.c:798 [inline] __x64_sys_pwrite64+0x1eb/0x250 fs/read_write.c:798 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f530cf9aeb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f530dd72028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00007f530d215fa0 RCX: 00007f530cf9aeb9 RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000010 RBP: 00007f530d008c1f R08: 0000000000000000 R09: 0000000000000000 R10: 4200000000000005 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f530d216038 R14: 00007f530d215fa0 R15: 00007ffde89fb978

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

April 24, 2026

Last Modified

April 27, 2026

Advisory Details (7)

Auto-updated Aug 2, 2026
No patch confirmed yet.
generic

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable. - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b94ae8e0d5fe1bdbbfdc3854ff6ce98f6876a828
generic

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable. - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b24763d32d5b4ada766deca4b42d6766272fef0c
generic

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable. - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8bb90ff77326c34e75b573b1febdd9586fec5aba
generic

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable. - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/787152497ac763deab16f6f4b7ce79aaeb3eb7e8
generic

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable. - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5ba05436f15d16ae7ab04b880e8bf8d440be892b
generic

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable. - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/29a1a350afcd28a2150bd73b8bd83eac3480f13e
generic

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable. - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/256f7d4c11235d0569f78413c41dc89d2dc1557c

Vendor Advisories for CVE-2026-31551(1)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 5.15.203—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux-6.16.1.106-3~deb11u1 ... 6.1.164-1~deb11u1 (16 versions)6.1.170-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (48 versions)6.1.170-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.85-1~bpo12+1 (17 versions)6.12.85-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (122 versions)6.19.10-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(24)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 6× in last 7d / 30× 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.

Showing the most recent 100 of 217 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 19:27 UTCEPSS rescore
  3. 2026-09-17 19:30 UTCEPSS rescore
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-13 16:47 UTCEPSS rescore
  7. 2026-09-12 15:01 UTCEPSS rescore
  8. 2026-09-11 14:52 UTCEPSS rescore
  9. 2026-09-10 09:34 UTCEPSS rescore
  10. 2026-09-08 22:00 UTCEPSS rescore
  11. 2026-09-07 16:01 UTCEPSS rescore
  12. 2026-09-06 13:47 UTCEPSS rescore
  13. 2026-09-06 13:47 UTCEPSS rescore
  14. 2026-09-04 05:06 UTCEPSS rescore
  15. 2026-09-04 03:16 UTCOSV refresh
  16. 2026-09-02 14:11 UTCEPSS rescore
  17. 2026-09-01 13:53 UTCEPSS rescore
  18. 2026-09-01 04:39 UTCEPSS rescore
  19. 2026-09-01 04:39 UTCEPSS rescore
  20. 2026-08-30 19:17 UTCEPSS rescore
  21. 2026-08-30 01:22 UTCEPSS rescore
  22. 2026-08-28 21:41 UTCEPSS rescore
  23. 2026-08-27 14:25 UTCEPSS rescore
  24. 2026-08-26 14:46 UTCEPSS rescore
  25. 2026-08-25 13:49 UTCEPSS rescore
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  1. 2026-08-24 14:17 UTCEPSS rescore
  2. 2026-08-23 00:19 UTCEPSS rescore
  3. 2026-08-21 23:49 UTCEPSS rescore
  4. 2026-08-20 22:55 UTCEPSS rescore
  5. 2026-08-20 22:55 UTCEPSS rescore
  6. 2026-08-19 17:03 UTCEPSS rescore
  7. 2026-08-18 13:48 UTCEPSS rescore
  8. 2026-08-17 14:52 UTCEG score recompute
  9. 2026-08-17 14:52 UTCVendor advisory
  10. 2026-08-17 14:52 UTCGHSA enrichment
  11. 2026-08-17 13:47 UTCEPSS rescore
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 05:48 UTCEG score recompute
  14. 2026-08-16 05:48 UTCVendor advisory
  15. 2026-08-16 05:48 UTCGHSA enrichment
  16. 2026-08-16 02:14 UTCEPSS rescore
  17. 2026-08-15 01:30 UTCEPSS rescore
  18. 2026-08-14 04:09 UTCEG score recompute
  19. 2026-08-14 04:09 UTCVendor advisory
  20. 2026-08-14 04:09 UTCGHSA enrichment
  21. 2026-08-13 22:00 UTCEPSS rescore
  22. 2026-08-12 17:52 UTCEG score recompute
  23. 2026-08-12 17:52 UTCVendor advisory
  24. 2026-08-12 17:52 UTCGHSA enrichment
  25. 2026-08-12 13:50 UTCEPSS rescore
  26. 2026-08-11 16:42 UTCEG score recompute
  27. 2026-08-11 16:42 UTCVendor advisory
  28. 2026-08-11 16:42 UTCGHSA enrichment
  29. 2026-08-11 00:00 UTCEPSS rescore
  30. 2026-08-10 12:47 UTCEG score recompute
  31. 2026-08-10 12:47 UTCVendor advisory
  32. 2026-08-10 12:47 UTCGHSA enrichment
  33. 2026-08-09 13:46 UTCEPSS rescore
  34. 2026-08-09 12:39 UTCEG score recompute
  35. 2026-08-09 12:39 UTCVendor advisory
  36. 2026-08-09 12:39 UTCGHSA enrichment
  37. 2026-08-08 16:37 UTCEPSS rescore
  38. 2026-08-08 12:17 UTCEG score recompute
  39. 2026-08-08 12:17 UTCVendor advisory
  40. 2026-08-08 12:17 UTCGHSA enrichment
  41. 2026-08-07 12:37 UTCEG score recompute
  42. 2026-08-07 12:37 UTCVendor advisory
  43. 2026-08-07 12:37 UTCGHSA enrichment
  44. 2026-08-06 13:46 UTCEPSS rescore
  45. 2026-08-05 22:57 UTCEG score recompute
  46. 2026-08-05 22:57 UTCVendor advisory
  47. 2026-08-05 22:57 UTCGHSA enrichment
  48. 2026-08-05 19:17 UTCEPSS rescore
  49. 2026-08-04 15:10 UTCEPSS rescore
  50. 2026-08-04 10:38 UTCEPSS rescore
  51. 2026-08-03 21:06 UTCEG score recompute
  52. 2026-08-03 21:06 UTCVendor advisory
  53. 2026-08-03 21:06 UTCGHSA enrichment
  54. 2026-08-03 10:36 UTCEPSS rescore
  55. 2026-08-02 11:26 UTCEG score recompute
  56. 2026-08-02 11:26 UTCVendor advisory
  57. 2026-08-02 11:26 UTCGHSA enrichment
  58. 2026-08-02 02:27 UTCEPSS rescore
  59. 2026-08-01 04:16 UTCEPSS rescore
  60. 2026-07-30 16:27 UTCEPSS rescore
  61. 2026-07-30 01:30 UTCEPSS rescore
  62. 2026-07-28 15:36 UTCEPSS rescore
  63. 2026-07-26 14:54 UTCEPSS rescore
  64. 2026-07-26 14:54 UTCEPSS rescore
  65. 2026-07-25 14:18 UTCEPSS rescore
  66. 2026-07-25 14:17 UTCEPSS rescore
  67. 2026-07-24 14:17 UTCEPSS rescore
  68. 2026-07-23 14:18 UTCEPSS rescore
  69. 2026-07-23 14:18 UTCEPSS rescore
  70. 2026-07-23 03:08 UTCEG score recompute
  71. 2026-07-22 14:08 UTCEPSS rescore
  72. 2026-07-22 14:08 UTCEPSS rescore
  73. 2026-07-21 15:24 UTCEPSS rescore
  74. 2026-07-21 15:24 UTCEPSS rescore
  75. 2026-07-20 17:08 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-31551?
CVE-2026-31551 is a medium vulnerability published on April 24, 2026. In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: Fix staticbranchdec() underflow for aql_disable. syzbot reported staticbranchdec() underflow in aqlenablewrite(). [0] The problem is that aqlenablewrite() does not serialise concurrent write()s to the debugfs.…
When was CVE-2026-31551 disclosed?
CVE-2026-31551 was first published in the National Vulnerability Database on April 24, 2026, with the most recent update on April 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31551 actively exploited?
CVE-2026-31551 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.7% of all scored CVEs.
What is the CVSS score of CVE-2026-31551?
CVE-2026-31551 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-31551?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31551, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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