CVE-2021-3995
First published: Tue Aug 23 2022(Updated: )
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.
Credit: secalert@redhat.com secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Kernel Util-linux | >=2.34<2.37.3 | |
| Fedoraproject Fedora | =35 |
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Reference Links
- 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://bugzilla.redhat.com/show_bug.cgi?id=2024631https://access.redhat.com/security/cve/CVE-2021-3995
- http://www.openwall.com/lists/oss-security/2022/11/30/2
- http://seclists.org/fulldisclosure/2022/Dec/4
- http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html
- https://security.netapp.com/advisory/ntap-20221209-0002/
- https://security.gentoo.org/glsa/202401-08
Frequently Asked Questions
What is the vulnerability ID for this logic error in the libmount library of util-linux?
The vulnerability ID for this logic error is CVE-2021-3995.
What is the severity of CVE-2021-3995?
The severity of CVE-2021-3995 is medium with a CVSS score of 5.5.
How does this vulnerability in the libmount library of util-linux impact affected systems?
This vulnerability allows an unprivileged local attacker to unmount FUSE filesystems that belong to certain other users with a UID prefix match.
Which software versions are affected by CVE-2021-3995?
Versions of util-linux up to and including 2.37.3 and Fedora 35 are affected by CVE-2021-3995.
Are there any references for CVE-2021-3995?
Yes, here are some references for CVE-2021-3995: [link1](http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html), [link2](http://seclists.org/fulldisclosure/2022/Dec/4), [link3](http://www.openwall.com/lists/oss-security/2022/11/30/2).
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- version/fedoraproject fedora/35