A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows a local user on a vulnerable system to unmount other users' filesystems that are either world-writable themselves (like /tmp) or mounted in a world-writable directory. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.
https://security.gentoo.org/glsa/202401-08
https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb
https://bugzilla.redhat.com/show_bug.cgi?id=2024628
https://access.redhat.com/security/cve/CVE-2021-3996
http://www.openwall.com/lists/oss-security/2022/11/30/2