# CVE-2026-98866: linux: In the Linux kernel, the following vulnerability has been resolved:  sched/cache: Introduce task_struct->sched_cache_...

CVE-2026-98866 is fixed in linux on 1 platform by DEBIAN-CVE-2026-98866 (version 7.2.10-1), released October 19, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-98866
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0015
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 18, 2026

## Description

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().

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.10-1 | [DEBIAN-CVE-2026-98866](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98866.md) | Oct 19, 2026 |

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Data as of 2026-11-09T13:31:49Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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