CVE-2021-39933

Name: CVE-2021-39933
Creator: NVD / NIST
Published: 2021-12-13T16:15:09.25+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.42%

Last modified Jun 17, 2026

CVE-2021-39933 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. An issue has been discovered in GitLab CE/EE affecting all versions starting from 12.10 before 14.3.6, all versions starting from 14.4 before 14.4.4, all versions starting from 14.5 before 14.5.2. A regular expression used for handling user input (notes, comments, etc) was susceptible to catastrophic backtracking that could cause a DOS attack.. EPSS estimates a 1.42% chance of exploitation in the next 30 days.

Description

An issue has been discovered in GitLab CE/EE affecting all versions starting from 12.10 before 14.3.6, all versions starting from 14.4 before 14.4.4, all versions starting from 14.5 before 14.5.2. A regular expression used for handling user input (notes, comments, etc) was susceptible to catastrophic backtracking that could cause a DOS attack.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

1.42%

69.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1333

Affected Software

Vendor	Product	Versions
Gitlab	Gitlab	>= 12.10.0, < 14.3.6
Gitlab	Gitlab	>= 14.4.0, < 14.4.4
Gitlab	Gitlab	>= 14.5.0, < 14.5.2

References

https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39933.jsonThird Party Advisory
https://gitlab.com/gitlab-org/gitlab/-/issues/340449Broken Link
https://hackerone.com/reports/1320077Permissions Required, Third Party Advisory
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39933.jsonThird Party Advisory
https://gitlab.com/gitlab-org/gitlab/-/issues/340449Broken Link
https://hackerone.com/reports/1320077Permissions Required, Third Party Advisory

Timeline

Published: Dec 13, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-39933?

How severe is CVE-2021-39933?

CVE-2021-39933 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.42% probability of exploitation in the next 30 days.

How do I fix CVE-2021-39933?

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-2021-39933?

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

Scan your code now

Source: NVD / NIST