CVE-2026-53129 – fs/mbcache: cancel shrink work before destroying the cache

CVE ID :CVE-2026-53129

Published : June 24, 2026, 4:30 p.m. | 1 hour, 13 minutes ago

Description :In the Linux kernel, the following vulnerability has been resolved:

fs/mbcache: cancel shrink work before destroying the cache

mb_cache_destroy() calls shrinker_free() and then frees all cache
entries and the cache itself, but it does not cancel the pending
c_shrink_work work item first.

If mb_cache_entry_create() schedules c_shrink_work via schedule_work()
and the work item is still pending or running when mb_cache_destroy()
runs, mb_cache_shrink_worker() will access the cache after its memory
has been freed, causing a use-after-free.

This is only reachable by a privileged user (root or CAP_SYS_ADMIN)
who can trigger the last put of a mounted ext2/ext4/ocfs2 filesystem.

Cancel the work item with cancel_work_sync() before calling
shrinker_free(), ensuring the worker has finished and will not be
rescheduled before the cache is torn down.

Severity: 0.0 | NA

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