Vulnerability · Published Aug 23, 2022 · Assigned by redhat
CVE-2021-3995
Medium 5.5
In plain English
A medium-severity security flaw in util-linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 51% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | util-linux | 2.37.3-r0 | ALPINE-CVE-2021-3995 |
| Alpine:v3.21 | util-linux | 2.37.3-r0 | ALPINE-CVE-2021-3995 |
| Alpine:v3.22 | util-linux | 2.37.3-r0 | ALPINE-CVE-2021-3995 |
| Alpine:v3.23 | util-linux | 2.37.3-r0 | ALPINE-CVE-2021-3995 |
| Alpine:v3.24 | util-linux | 2.37.3-r0 | ALPINE-CVE-2021-3995 |
| Debian:12 | util-linux | 2.37.3-1 | DEBIAN-CVE-2021-3995 |
| Debian:13 | util-linux | 2.37.3-1 | DEBIAN-CVE-2021-3995 |
| Debian:14 | util-linux | 2.37.3-1 | DEBIAN-CVE-2021-3995 |
| Ubuntu:22.04:LTS | util-linux | 2.37.2-4ubuntu2 | UBUNTU-CVE-2021-3995 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| n/a | util-linux | Fixed in util-linux v2.37.3 |
Weakness: CWE-552
References
- 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
- [oss-security] 20221130 Race condition in snap-confine's must_mkdir_and_open_with_perms() (CVE-2022-3328) mailing-list
- 20221208 Race condition in snap-confine's must_mkdir_and_open_with_perms() (CVE-2022-3328) mailing-list
- http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html
- https://security.netapp.com/advisory/ntap-20221209-0002/
- GLSA-202401-08 vendor-advisory