CVE-2021-3996: Medium severity util-linux vulnerability
A flaw was found in util-linux's libmount. An issue related to parsing the /proc/self/mountinfo file allows an unprivileged user to unmount other users' filesystems that are either world-writable themselves (like /tmp) or mounted in a world-writable directory.
Other sources
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.
— MITRE
Affected Software
Remediation
Patch Available
Patch Available
Event History
Frequently Asked Questions
What is the vulnerability ID?
The vulnerability ID is CVE-2021-3996.
What is the title of the vulnerability?
The title of the vulnerability 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.'
What is the severity of CVE-2021-3996?
The severity of CVE-2021-3996 is medium, with a severity value of 5.5.
What is the affected software?
The affected software includes Kernel Util-linux version 2.34 to 2.37.3, Fedoraproject Fedora version 35, and redhat/util-linux version up to 2.37.3.
How can this vulnerability be exploited?
This vulnerability can be exploited by a local user on a vulnerable system to unmount other users' filesystems that are either world-writable themselves or mounted in a specific way.