CVE-2021-4149

Name: CVE-2021-4149
Creator: NVD / NIST
Published: 2022-03-23T20:15:09.997+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.40%

Last modified Jun 17, 2026

CVE-2021-4149 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. A vulnerability was found in btrfs_alloc_tree_b in fs/btrfs/extent-tree.c in the Linux kernel due to an improper lock operation in btrfs. In this flaw, a user with a local privilege may cause a denial of service (DOS) due to a deadlock problem.. EPSS estimates a 0.40% chance of exploitation in the next 30 days.

Description

A vulnerability was found in btrfs_alloc_tree_b in fs/btrfs/extent-tree.c in the Linux kernel due to an improper lock operation in btrfs. In this flaw, a user with a local privilege may cause a denial of service (DOS) due to a deadlock problem.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.40%

31.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	< 5.15
Linux	Linux Kernel	5.15
Debian	Debian Linux	9.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=2026485Issue Tracking, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/07/msg00000.htmlMailing List, Third Party Advisory
https://lkml.org/lkml/2021/10/18/885Exploit, Mailing List, Patch, Third Party Advisory
https://lkml.org/lkml/2021/9/13/2565Exploit, Mailing List, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2026485Issue Tracking, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/07/msg00000.htmlMailing List, Third Party Advisory
https://lkml.org/lkml/2021/10/18/885Exploit, Mailing List, Patch, Third Party Advisory
https://lkml.org/lkml/2021/9/13/2565Exploit, Mailing List, Third Party Advisory

Timeline

Published: Mar 23, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-4149?

How severe is CVE-2021-4149?

CVE-2021-4149 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.40% probability of exploitation in the next 30 days.

How do I fix CVE-2021-4149?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-4149?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST