SB2026062523 - Use-after-free in Linux kernel fs

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-53129)

CWE-ID: CWE-416 - Use After Free

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local privileged user to cause a denial of service.

The vulnerability exists due to use-after-free in mb_cache_destroy() and mb_cache_shrink_worker() when destroying an mbcache instance while scheduled shrink work is pending or running. A local privileged user can trigger the last put of a mounted ext2, ext4, or ocfs2 filesystem to cause a denial of service.

The issue is only reachable when the attacker can trigger teardown of the cache for a mounted filesystem.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/0e4eff315d799f5842b95872199b0f0fb8ef5f51
• https://git.kernel.org/stable/c/a88d39a74a208e197c03bffaa2df34de732af19f
• https://git.kernel.org/stable/c/b25fd3523bef88fb7ffd4c5b63bbe9c08f73bb4c
• https://git.kernel.org/stable/c/d227786ab1119669df4dc333a61510c52047cce4