sched/cache: Introduce task_struct->sched_cache_grp to fix UAF
In the Linux kernel, the following vulnerability has been resolved: sched/cache: Introduce task_struct->sched_cache_grp to fix UAF Add a sched_cache_grp pointer to task_struct so that scheduler code can access the cache group directly via the task, without going through mm->sched_cache_grp. This decouples the scheduler's hot-path accesses from the mm_struct. Each task holds its own refcount on the sched_cache_group, separate from the reference held by its mm_struct. The reference is acquired in copy_mm() (fork) and exec_mmap() (exec), and released in exit_mm(). This fixes the use-after-free when account_mm_sched() reaches the group through a task whose mm is being switched, as reported by Hyunwoo: https://lore.kernel.org/lkml/apPb-Dr4nPYuHQOK@v4bel/ Convert all scheduler code in fair.c and exit.c to use p->sched_cache_grp instead of p->mm->sched_cache_grp. Keep the fork/exec/exit reference management out of the generic mm paths: add sched_cache_fork(), sched_cache_fork_cleanup(), sched_cache_exec_mmap() and sched_cache_exit_mm() in kernel/sched/cache_sched.c (with empty stubs for !CONFIG_SCHED_CACHE), so fs/exec.c, kernel/fork.c and kernel/exit.c each call one helper instead of open-coding the refcounting under #ifdef. Also add sched_cache_group_get() and task_cache_group_get().
CVE-2026-98866
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-2026-98866
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": "df0d98475954d655571979aa061ecb07d7e00392",
"lessThan": "9436130e6da72af63289a4acb3aa0c1df07a3928",
"versionType": "git"
},
{
"status": "affected",
"version": "df0d98475954d655571979aa061ecb07d7e00392",
"lessThan": "b636fef85bda7d1bab9c0a45067ab1508d79d946",
"versionType": "git"
}
],
"programFiles": [
"fs/exec.c",
"include/linux/sched.h",
"kernel/exit.c",
"kernel/fork.c",
"kernel/sched/fair.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7.2"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "7.2",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "7.2.10",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/exec.c",
"include/linux/sched.h",
"kernel/exit.c",
"kernel/fork.c",
"kernel/sched/fair.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98866
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38760 · Revision 1
- Added to Heist Feed
- Publisher date