util-linux versions through 2.41.5 and 2.42.2 fail to check mount helper exit status before running post-mount hooks, allowing unprivileged users to execute privileged operations on pre-existing filesystems. Attackers can exploit X-mount.idmap or X-mount.owner hooks to clone filesystems with inherited suid bits or modify target inode permissions after a helper fails, achieving privilege escalation.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
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 v4.0
Weakness Type (CWE)
References 8
https://github.com/util-linux/util-linux
disclosure@vulncheck.com
https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_moun…
disclosure@vulncheck.com
https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_moun…
disclosure@vulncheck.com
https://github.com/util-linux/util-linux/commit/1d14676ea70003e9f5b2a6a76af0cad…
disclosure@vulncheck.com
https://github.com/util-linux/util-linux/commit/a15c00a9e545aa8b9cf6ec0f888ff6c…
disclosure@vulncheck.com
https://github.com/util-linux/util-linux/commit/f57cea130839c0af8dc0525274267ae…
disclosure@vulncheck.com
https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/util-linux-libmount-privilege-escalation-v…
disclosure@vulncheck.com