CVE-2021-39939

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% 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-400

Description

An uncontrolled resource consumption vulnerability in GitLab Runner affecting all versions starting from 13.7 before 14.3.6, all versions starting from 14.4 before 14.4.4, all versions starting from 14.5 before 14.5.2, allows an attacker triggering a job with a specially crafted docker image to exhaust resources on runner manager

Affected products

GitLab: from 13.7.0 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-2021-39939.json
https://gitlab.com/gitlab-org/gitlab-runner/-/issues/28630
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39939.json
https://gitlab.com/gitlab-org/gitlab-runner/-/issues/28630

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