CVE-2021-3995
What it is
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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.
- Exploit odds
- 0.6% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.6% in the next 30 days (EPSS).
- Severity: 5.5 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.6% · EPSS, next 30 days
- Weakness
- CWE-552
- Record status
- Modified
Affected
- Kernel util-linux < 2.37.3
- Fedoraproject Fedora 35
Attack profile CVSS 3.1 · 5.5
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-3995.md and follow it. Check whether this project is affected by CVE-2021-3995. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d
- 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
- https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d
- 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
References
- http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html
- http://seclists.org/fulldisclosure/2022/Dec/4
- http://www.openwall.com/lists/oss-security/2022/11/30/2
- https://bugzilla.redhat.com/show_bug.cgi?id=2024631https://access.redhat.com/security/cve/CVE-2021-3995
- https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d
- https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes
- https://security.gentoo.org/glsa/202401-08
- https://security.netapp.com/advisory/ntap-20221209-0002/
- https://www.openwall.com/lists/oss-security/2022/01/24/2
- http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html
- http://seclists.org/fulldisclosure/2022/Dec/4
- http://www.openwall.com/lists/oss-security/2022/11/30/2
- https://bugzilla.redhat.com/show_bug.cgi?id=2024631https://access.redhat.com/security/cve/CVE-2021-3995
- https://github.com/util-linux/util-linux/commit/57202f5713afa2af20ffbb6ab5331481d0396f8d
- https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes
- https://security.gentoo.org/glsa/202401-08
- https://security.netapp.com/advisory/ntap-20221209-0002/
- https://www.openwall.com/lists/oss-security/2022/01/24/2