CVE-2026-68179: Linux kernel · misc: nsm: only unlock nsm_dev on post-lock error paths
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.4 High · fixed in f318f5a872cb9096536e759b23ae5c9873bb80ed : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:30 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% 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
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in f318f5a872cb9096536e759b23ae5c9873bb80ed, ce1fed11d18e163baf7f875152a33bf80f625c1a, 8f068342096b027181b168d91fef7ac7a2c64b25 +1
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 10 Aug 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 Linux kernel to f318f5a872cb9096536e759b23ae5c9873bb80ed, ce1fed11d18e163baf7f875152a33bf80f625c1a, 8f068342096b027181b168d91fef7ac7a2c64b25 or 4aa3f7d48e91eb74a363c1b4d7dbdd28f5b341fb.
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– |
Description
In the Linux kernel, the following vulnerability has been resolved: misc: nsm: only unlock nsm_dev on post-lock error paths nsm_dev_ioctl() jumps to the common out label even when the initial copy_from_user() fails before nsm->lock has been taken. The error path then blindly unlocks a mutex that was never acquired. This issue was found by our static analysis tool and then manually reviewed against the current tree. The grounded PoC kept the miscdevice ioctl entry and the pre-lock copy_from_user(&raw, argp, _IOC_SIZE(cmd)) failure path by issuing NSM_IOCTL_RAW with an invalid user pointer. That failure reaches the shared out label before mutex_lock(&nsm->lock). Lockdep reported: WARNING: bad unlock balance detected! exploit/193 is trying to release lock (&global_nsm.lock) at: nsm_dev_ioctl+0x5f/0xcf [vuln_msv] but there are no more locks to release! no locks held by exploit/193. Return immediately on the pre-lock copy_from_user() failure and keep the common unlock label for the post-lock paths only.
References
- git.kernel.org/stable/c/4aa3f7d48e91eb74a363c1b4d7dbdd28f5b341fb (opens in a new tab)
- git.kernel.org/stable/c/8f068342096b027181b168d91fef7ac7a2c64b25 (opens in a new tab)
- git.kernel.org/stable/c/f318f5a872cb9096536e759b23ae5c9873bb80ed (opens in a new tab)
- git.kernel.org/stable/c/ce1fed11d18e163baf7f875152a33bf80f625c1a (opens in a new tab)