Vulnerability Details : CVE-2021-3996
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.
Vulnerability category: Denial of service
Products affected by CVE-2021-3996
- cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
- cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-3996
0.04%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 6 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-3996
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
5.5
|
MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
1.8
|
3.6
|
134c704f-9b21-4f2e-91b3-4a467353bcc0 | 2024-10-15 |
|
5.5
|
MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
1.8
|
3.6
|
NIST |
CWE ids for CVE-2021-3996
-
The product makes files or directories accessible to unauthorized actors, even though they should not be.Assigned by:
- nvd@nist.gov (Secondary)
- secalert@redhat.com (Primary)
References for CVE-2021-3996
-
https://security.netapp.com/advisory/ntap-20221209-0002/
August 2022 Util-linux Vulnerabilities in NetApp Products | NetApp Product SecurityBroken Link;Third Party Advisory
-
http://seclists.org/fulldisclosure/2022/Dec/4
Full Disclosure: Race condition in snap-confine's must_mkdir_and_open_with_perms() (CVE-2022-3328)Mailing List;Third Party Advisory
-
https://security.gentoo.org/glsa/202401-08
util-linux: Multiple Vulnerabilities (GLSA 202401-08) — Gentoo security
-
https://bugzilla.redhat.com/show_bug.cgi?id=2024628
2024628 – (CVE-2021-3996) CVE-2021-3996 util-linux: Unauthorized unmount of filesystems in libmountIssue Tracking;Patch;Third Party Advisory
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https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb
libmount: remove support for deleted mount table entries · util-linux/util-linux@166e873 · GitHubPatch;Third Party Advisory
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https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes
Release Notes;Vendor Advisory
-
https://access.redhat.com/security/cve/CVE-2021-3996
CVE-2021-3996- Red Hat Customer PortalIssue Tracking;Third Party Advisory
-
http://www.openwall.com/lists/oss-security/2022/11/30/2
oss-security - Race condition in snap-confine's must_mkdir_and_open_with_perms() (CVE-2022-3328)Mailing List;Third Party Advisory
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https://www.openwall.com/lists/oss-security/2022/01/24/2
oss-security - CVE-2021-3996 and CVE-2021-3995 in util-linux's libmountExploit;Mailing List;Patch;Third Party Advisory
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http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html
snap-confine must_mkdir_and_open_with_perms() Race Condition ≈ Packet StormThird Party Advisory
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