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.