CVE-2021-3996

MEDIUM
Published Aug 23, 20223y ago · Modified Jun 17, 20262w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Aug 23, 2022 3y ago
Last Modified Jun 17, 2026 2w ago

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 Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

No active exploitation signals — not in CISA KEV and no EPSS score yet.

Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-552

Affected Products 2

VendorProductVersionRange
kernelutil-linux*≥2.34  –  <2.37.3
fedoraprojectfedora35any

References 10

  • packetstormsecurity.com http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html
    Third Party Advisory
  • seclists.org http://seclists.org/fulldisclosure/2022/Dec/4
    Mailing ListThird Party Advisory
  • openwall.com http://www.openwall.com/lists/oss-security/2022/11/30/2
    Mailing ListThird Party Advisory
  • access.redhat.com https://access.redhat.com/security/cve/CVE-2021-3996
    Issue TrackingThird Party Advisory
  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=2024628
    Issue TrackingPatchThird Party Advisory
  • github.com https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb
    PatchThird Party Advisory
  • mirrors.edge.kernel.org https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes
    Release NotesVendor Advisory
  • security.gentoo.org https://security.gentoo.org/glsa/202401-08
  • security.netapp.com https://security.netapp.com/advisory/ntap-20221209-0002/
    Broken LinkThird Party Advisory
  • openwall.com https://www.openwall.com/lists/oss-security/2022/01/24/2
    ExploitMailing ListPatchThird Party Advisory

Remediation

  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=2024628
    Issue TrackingPatchThird Party Advisory
  • github.com https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb
    PatchThird Party Advisory
  • openwall.com https://www.openwall.com/lists/oss-security/2022/01/24/2
    ExploitMailing ListPatchThird Party Advisory