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CVE-2026-53612

util-linux mount hook_owner TOCTOU allows local privilege escalation PUBLISHED

Description (CNA)

util-linux is a random collection of Linux utilities. In util-linux 2.39 through 2.41.4 and 2.42 through 2.42.1, the SUID `mount` utility's `hook_owner.c` post-mount hook performs path-based `chmod()` and `lchown()` operations on a previously validated mount target. A local low-privileged user authorized by an `/etc/fstab` entry with `user` or `users` and an `X-mount.mode`, `X-mount.owner`, or `X-mount.group` option can use `renameat2(RENAME_EXCHANGE)` to race a writable ancestor of the target and redirect the privileged ownership or mode change to a root-owned path, potentially gaining root privileges. This issue is fixed in 2.41.5 and 2.42.2.

Affected (CNA)

Vendor / productVersions
util-linux / util-linuxaffected >= 2.39, < 2.41.5; affected >= 2.42, < 2.42.2

CWE

CWE-367

References

ADP enrichment

CISA-ADP

No English description supplied.