| Name | CVE-2021-3996 |
| Description | 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. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DSA-5055-1 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| util-linux (PTS) | jessie, jessie (lts) | 2.26.2+really2.25.2-6+deb8u2 | fixed |
| stretch (security) | 2.29.2-1+deb9u1 | fixed |
| stretch (lts), stretch | 2.29.2-1+deb9u3 | fixed |
| buster (security), buster, buster (lts) | 2.33.1-0.1+deb10u1 | fixed |
| bullseye (security), bullseye | 2.36.1-8+deb11u2 | fixed |
| bookworm | 2.38.1-5+deb12u2 | fixed |
| bookworm (security) | 2.38.1-5+deb12u1 | fixed |
| sid, trixie | 2.40.2-12 | fixed |
The information below is based on the following data on fixed versions.
Notes
[buster] - util-linux <not-affected> (Vulnerable code introduced later)
[stretch] - util-linux <not-affected> (Vulnerable code introduced later)
Introduced by: https://github.com/util-linux/util-linux/commit/5fea669e9ef0a08804f72bb40f859f239f68c30a (v2.34-rc1)
Fixed by: https://github.com/util-linux/util-linux/commit/018a10907fa9885093f6d87401556932c2d8bd2b (v2.37.3)
https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes
https://www.openwall.com/lists/oss-security/2022/01/24/2
[jessie] - util-linux <not-affected> (Vulnerable code introduced later)