posix-cpu-timers: Prevent freeing a timer which is queued on the expiry list
In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: Prevent freeing a timer which is queued on the expiry list Kijo analyzed another race in the POSIX CPU timer code: Commit bf635681c906 converted cpu_timer::firing from a tristate value to a boolean. This lost the distinction between "not owned by the firing list" and "still owned, but delivery was canceled". The resulting race is: expiry handler timer_settime() timer_delete() -------------- --------------- -------------- collect timer onto private firing list firing = true observes firing = true firing = false return TIMER_RETRY wait for handler observes firing = false finish deletion unhash and free timer resume list traversal read freed elist.next -> UAF The firing bit is clearly the wrong indicator since that commit. Check whether the timer is queued on the expiry list or not instead. If it is queued clear the firing bit to prevent signal delivery as before and return TIMER_RETRY so the caller unlocks the timer which allows the expiry code to make progress and remove it from the list.
CVE-2026-98258
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-2026-98258
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": "bf635681c906ad056d1fda325de8d1c12c9f8201",
"lessThan": "9971dac1a77845ff467146915fcbb9170f6a8209",
"versionType": "git"
},
{
"status": "affected",
"version": "bf635681c906ad056d1fda325de8d1c12c9f8201",
"lessThan": "4336e3f47d9d516441066e9a65eaf076790d8d45",
"versionType": "git"
},
{
"status": "affected",
"version": "bf635681c906ad056d1fda325de8d1c12c9f8201",
"lessThan": "c21eaa72f02fc6e85621cbe09d303d8fb8bd39cd",
"versionType": "git"
}
],
"programFiles": [
"kernel/time/posix-cpu-timers.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.13"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.13",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.54",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.8",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"kernel/time/posix-cpu-timers.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98258
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #38337 · Revision 1
- Added to Heist Feed
- Publisher date