CVE-2026-31486: Linux kernel · hwmon: (pmbus/core) Protect regulator operations with mutex
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.1 High · fixed in b26849cffaa7c43355b82e9bef3725e786973a1a : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:18 UTC
- EPSS
- 0.09% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- 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, 2026-10-16.
- Patch
- Available – fixed in b26849cffaa7c43355b82e9bef3725e786973a1a, acf04e2863132f6d9222f71f3a76fb9782cbe061, 754bd2b4a084b90b5e7b630e1f423061a9b9b761 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 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– |
AI-suggested
A fix is available and has been applied in Linux kernel version 3.19 and subsequent commits. Users and administrators should update to these fixed versions to mitigate the race condition and deadlock issues. No additional action is required beyond applying the official patch. Since this is a kernel-level fix, ensure that kernel updates are tested and deployed according to organizational policies.
Description
CVE-2026-31486 is a high-severity vulnerability in the Linux kernel's hwmon subsystem related to PMBus regulator operations. The issue arises because certain regulator functions accessing shared PMBus registers were not protected by a mutex, leading to potential race conditions. A direct mutex addition caused deadlocks due to nested locking scenarios. The fix reworks notification handling to use a worker function outside the mutex, preventing deadlocks and ensuring safe concurrent access.
References
- git.kernel.org/stable/c/b26849cffaa7c43355b82e9bef3725e786973a1a (opens in a new tab)
- git.kernel.org/stable/c/acf04e2863132f6d9222f71f3a76fb9782cbe061 (opens in a new tab)
- git.kernel.org/stable/c/4e9d723d9f198b86f6882a84c501ba1f39e8d055 (opens in a new tab)
- git.kernel.org/stable/c/2c77ae315f3ce9d2c8e1609be74c9358c1fe4e07 (opens in a new tab)
- git.kernel.org/stable/c/754bd2b4a084b90b5e7b630e1f423061a9b9b761 (opens in a new tab)