What is CVE-2021-39939?

CVE-2021-39939 is a medium-severity vulnerability in GitLab, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2021-12-13.

How severe is CVE-2021-39939?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Resource exhaustion in GitLab

CVE-2021-39939

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

Vulnerability class: DoS (Denial of Service)

Published 2021-12-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.009 (58.3th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 58.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

GitLab
GitLab Runner — versions >=13.7, <14.3.6, >=14.4, <14.4.4, >=14.5, <14.5.2

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

References

gitlab.com/gitlab-org/gitlab-runner/-/issues/28630 (Broken Link)
gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39939.json (Third Party Advisory)

Frequently asked questions

What is CVE-2021-39939?: CVE-2021-39939 is a medium-severity vulnerability in GitLab, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2021-12-13.
How severe is CVE-2021-39939?: Medium severity. CVSS v3 base score is 6.5 out of 10.