misc: nsm: only unlock nsm_dev on post-lock error paths
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.
CVE-2026-68179
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-68179
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "b9873755a6c8ccfce79094c4dce9efa3ecb1a749",
"lessThan": "4aa3f7d48e91eb74a363c1b4d7dbdd28f5b341fb",
"versionType": "git"
},
{
"status": "affected",
"version": "b9873755a6c8ccfce79094c4dce9efa3ecb1a749",
"lessThan": "8f068342096b027181b168d91fef7ac7a2c64b25",
"versionType": "git"
},
{
"status": "affected",
"version": "b9873755a6c8ccfce79094c4dce9efa3ecb1a749",
"lessThan": "f318f5a872cb9096536e759b23ae5c9873bb80ed",
"versionType": "git"
},
{
"status": "affected",
"version": "b9873755a6c8ccfce79094c4dce9efa3ecb1a749",
"lessThan": "ce1fed11d18e163baf7f875152a33bf80f625c1a",
"versionType": "git"
}
],
"programFiles": [
"drivers/misc/nsm.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/misc/nsm.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-68179
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #41150 · Revision 1
- Added to Heist Feed
- Publisher date