Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Kernel | Util-Linux | >= 2.34, < 2.37.3 |
| Fedoraproject | Fedora | 35 |
Related Weaknesses (CWE)
References
- http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_witThird Party Advisory
- http://seclists.org/fulldisclosure/2022/Dec/4Mailing ListThird Party Advisory
- http://www.openwall.com/lists/oss-security/2022/11/30/2Mailing ListThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2021-3996Issue TrackingThird Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2024628Issue TrackingPatchThird Party Advisory
- https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceaePatchThird Party Advisory
- https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseRelease NotesVendor Advisory
- https://security.gentoo.org/glsa/202401-08
- https://security.netapp.com/advisory/ntap-20221209-0002/Broken LinkThird Party Advisory
- https://www.openwall.com/lists/oss-security/2022/01/24/2ExploitMailing ListPatch
- http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_witThird Party Advisory
- http://seclists.org/fulldisclosure/2022/Dec/4Mailing ListThird Party Advisory
- http://www.openwall.com/lists/oss-security/2022/11/30/2Mailing ListThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2021-3996Issue TrackingThird Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2024628Issue TrackingPatchThird Party Advisory
FAQ
What is CVE-2021-3996?
CVE-2021-3996 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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 unm...
How severe is CVE-2021-3996?
CVE-2021-3996 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-3996?
Check the references section above for vendor advisories and patch information. Affected products include: Kernel Util-Linux, Fedoraproject Fedora.