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 an unprivileged local attacker to unmount FUSE filesystems that belong to certain other users who have a UID that is a prefix of the UID of the attacker in its string form. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.
Cite this page
CVE-2021-3995. CVEDatabase.com. Retrieved 1 May 2026. https://cvedatabase.com/cve/CVE-2021-3995
Use CWE-552, Kernel vendor hub and Util-Linux product page to widen CVE-2021-3995 into its surrounding weakness, vendor, and product context.
Compare it with CVE-2015-5224, CVE-2018-7738 and CVE-2014-9114 for nearby disclosures in the same product family.