What is CVE-2021-39902?

CVE-2021-39902 is a medium-severity vulnerability in GitLab, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2021-11-04.

How severe is CVE-2021-39902?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Auth bypass in GitLab

CVE-2021-39902

Incorrect Authorization in GitLab CE/EE 13.4 or above allows a user with guest membership in a project to modify the severity of an incident.

Vulnerability class: Broken Access Control

Published 2021-11-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.008 (54.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

GitLab — versions 14.4.0, >=13.4, <14.2.6, >=14.3, <14.3.4

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

gitlab.com/gitlab-org/gitlab/-/issues/341479 (Broken Link)
hackerone.com/reports/1341674 (Permissions Required, Third Party Advisory)
gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39902.json (Vendor Advisory)

Frequently asked questions

What is CVE-2021-39902?: CVE-2021-39902 is a medium-severity vulnerability in GitLab, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2021-11-04.
How severe is CVE-2021-39902?: Medium severity. CVSS v3 base score is 4.3 out of 10.