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.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
High
Difficult to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v3.1
Weakness Type (CWE)
References 7
https://github.com/util-linux/util-linux/commit/24da33905c7115c4cbccd0afb2a4698…
security-advisories@github.com
https://github.com/util-linux/util-linux/commit/722c96974dd4009a334e4aee556eeda…
security-advisories@github.com
https://github.com/util-linux/util-linux/commit/897a08c2b11dfa66975c3d24d63c7bf…
security-advisories@github.com
https://github.com/util-linux/util-linux/commit/d0c5adaeb3a3d823aba1377794de8f0…
security-advisories@github.com
https://github.com/util-linux/util-linux/releases/tag/v2.41.5
security-advisories@github.com
https://github.com/util-linux/util-linux/releases/tag/v2.42.2
security-advisories@github.com
https://github.com/util-linux/util-linux/security/advisories/GHSA-g8wm-75wr-g2vh
security-advisories@github.com