CVE-2021-3996: Fedoraproject Fedora

Medium severity, CVSS 5.5. EPSS: 0.6% chance of exploitation in the next 30 days.

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.

Affected products

• Fedoraproject Fedora: version 35 only
• Kernel Util-Linux: from 2.34, before 2.37.3 (fixed in 2.37.3)

Published 2022-08-23. Last modified 2026-06-17.