CVE-2026-31551: Linux kernel · wifi: mac80211: Fix static_branch_dec() underflow for aql_disable.
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in b24763d32d5b4ada766deca4b42d6766272fef0c : update Linux kernel when convenient.
Data as of 5 Nov 2026, 22:06 UTC
Rated Low by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-05.
- Patch
- Available – fixed in b24763d32d5b4ada766deca4b42d6766272fef0c, b94ae8e0d5fe1bdbbfdc3854ff6ce98f6876a828, 787152497ac763deab16f6f4b7ce79aaeb3eb7e8 +4
Exploitation evidence
Disclosed: evidence found.
CVE published 24 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
This vulnerability has been fixed in the Linux kernel. Users should update to a fixed kernel version containing the patches identified by the provided commit hashes. No additional mitigation steps are required beyond applying the official fix.
Description
A vulnerability in the Linux kernel's mac80211 wifi subsystem was fixed to address a static_branch_dec() underflow caused by improper serialization of concurrent writes to debugfs. The issue occurred because aql_enable_write() did not properly synchronize state changes between checks and static branch counter adjustments, potentially leading to underflow. The fix replaces manual increment/decrement calls with static_branch_enable() and static_branch_disable() to ensure correct state management.
References
- git.kernel.org/stable/c/787152497ac763deab16f6f4b7ce79aaeb3eb7e8 (opens in a new tab)
- git.kernel.org/stable/c/8bb90ff77326c34e75b573b1febdd9586fec5aba (opens in a new tab)
- git.kernel.org/stable/c/256f7d4c11235d0569f78413c41dc89d2dc1557c (opens in a new tab)
- git.kernel.org/stable/c/29a1a350afcd28a2150bd73b8bd83eac3480f13e (opens in a new tab)
- git.kernel.org/stable/c/5ba05436f15d16ae7ab04b880e8bf8d440be892b (opens in a new tab)
- git.kernel.org/stable/c/b24763d32d5b4ada766deca4b42d6766272fef0c (opens in a new tab)
- git.kernel.org/stable/c/b94ae8e0d5fe1bdbbfdc3854ff6ce98f6876a828 (opens in a new tab)