CVE-2021-3995 is a logic error in the libmount library of util-linux, affecting Fedora and kernel util-linux packages. This flaw allows an unprivileged local attacker to unmount FUSE filesystems belonging to other users whose UID is a string prefix of the attacker's UID. The vulnerability has a CVSS score of 5.5 (Medium) and can lead to a denial of service for applications using affected filesystems. There is no public exploit code available, nor is it listed on the KEV catalog, indicating no active exploitation. However, it has garnered some community discussion and media coverage, suggesting awareness of the issue.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
>= 2.34, < 2.37.3CPE matchmatch criteria | cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:* | ||
35CPE matchmatch criteria | cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.
The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.
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.
Aug 9, 2022util-linux: Unauthorized unmount of FUSE filesystems belonging to users with similar uid
Jan 24, 2022