CVE-2021-39910

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-12-13 · updated 2026-06-17
Weakness: CWE-79

Description

An issue has been discovered in GitLab CE/EE affecting all versions starting from 12.6 before 14.3.6, all versions starting from 14.4 before 14.4.4, all versions starting from 14.5 before 14.5.2. GitLab was vulnerable to HTML Injection through the Swagger UI feature.

Affected products

GitLab: from 12.6.0 before 14.3.6; from 14.4.0 before 14.4.4; from 14.5.0 before 14.5.2 — fixed in 14.3.6, 14.4.4, 14.5.2

How to fix

Upgrade to a fixed version: GitLab 14.3.6, 14.4.4, 14.5.2. Check the vendor advisory for mitigations.

References

https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39910.json
https://gitlab.com/gitlab-org/gitlab/-/issues/325901
https://hackerone.com/reports/1133656
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39910.json
https://gitlab.com/gitlab-org/gitlab/-/issues/325901
https://hackerone.com/reports/1133656

Get alerted when CVE-2021-39910 or the next vulnerability affects your stack