fsnotify: Fix stale object mask after concurrent mark updates
In the Linux kernel, the following vulnerability has been resolved: fsnotify: Fix stale object mask after concurrent mark updates When a mark gets a new event bit, fanotify and inotify may avoid recalculating the object mask if the cached aggregate already contains that bit. This is racy with a recalculation triggered by a concurrent update to another mark on the same connector. The concurrent scan can read the mark before the new bit is added, while the updater reads the old aggregate before that scan publishes its result. The updater then skips recalculation and the scan publishes a mask without the bit, leaving the object mask stale after both updates complete. This can be reproduced with two fanotify groups watching the same inode: one thread removes FAN_MODIFY from one existing mark while another thread adds FAN_MODIFY to the other mark. After both fanotify_mark() calls return, writes can fail to produce FAN_MODIFY for the group whose mark now contains the bit. This was reproduced on an unmodified v6.12.95 kernel. The equivalent inotify interleaving loses IN_MODIFY events. For normal fanotify additions, recalculate whenever the raw mark mask changes. The normal mask is not cleared asynchronously, so an unchanged addition cannot introduce missing interest. Always recalculate ignore-mask updates because FS_MODIFY handling may clear the ignore mask without taking mark->lock, making snapshot comparisons unreliable. Always recalculate after updating an existing inotify watch.
CVE-2026-89595
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-2026-89595
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": "63c882a05416e18de6fb59f7dd6da48f3bbe8273",
"lessThan": "27d172b60eeca5c8fd51b246f9fb959067cf102b",
"versionType": "git"
},
{
"status": "affected",
"version": "63c882a05416e18de6fb59f7dd6da48f3bbe8273",
"lessThan": "2f09f08d602647fc4e328fc27ecb4c3008d10338",
"versionType": "git"
},
{
"status": "affected",
"version": "63c882a05416e18de6fb59f7dd6da48f3bbe8273",
"lessThan": "de75382d6e354b2b055df4896d12a91969f12090",
"versionType": "git"
},
{
"status": "affected",
"version": "63c882a05416e18de6fb59f7dd6da48f3bbe8273",
"lessThan": "343ae18e960f6c5f1d34d58a69750c62cd463228",
"versionType": "git"
},
{
"status": "affected",
"version": "63c882a05416e18de6fb59f7dd6da48f3bbe8273",
"lessThan": "92289e66639f62abc754c6f3bce5ead7e98e4ee2",
"versionType": "git"
},
{
"status": "affected",
"version": "63c882a05416e18de6fb59f7dd6da48f3bbe8273",
"lessThan": "947400af98b9e63841929d079a2c3ea0a8ba227b",
"versionType": "git"
},
{
"status": "affected",
"version": "63c882a05416e18de6fb59f7dd6da48f3bbe8273",
"lessThan": "ac8d8b599d466a129122bded77db3d0f8b96b461",
"versionType": "git"
},
{
"status": "affected",
"version": "63c882a05416e18de6fb59f7dd6da48f3bbe8273",
"lessThan": "e422777fdd4746de1109575c51e65038d4c5c1be",
"versionType": "git"
}
],
"programFiles": [
"fs/notify/fanotify/fanotify_user.c",
"fs/notify/inotify/inotify_user.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.31"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.31",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.270",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.221",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.110",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.51",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/notify/fanotify/fanotify_user.c",
"fs/notify/inotify/inotify_user.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89595
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #35103 · Revision 1
- Added to Heist Feed
- Publisher date