What is CVE-2018-20489?

CVE-2018-20489 is a medium-severity vulnerability in GitLab, classified under Improper Authentication. CVSS score: 5.3/10. Published 2019-12-30.

How severe is CVE-2018-20489?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Auth bypass in GitLab

CVE-2018-20489

An issue was discovered in GitLab Community and Enterprise Edition before 11.4.13, 11.5.x before 11.5.6, and 11.6.x before 11.6.1. It has Incorrect Access Control.

Vulnerability class: Broken Authentication

Published 2019-12-30 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.008 (54.0th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.0% 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

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

about.gitlab.com/2018/12/31/security-release-gitlab-11-dot-6-dot-1-released/ (Vendor Advisory)
gitlab.com/gitlab-org/gitlab-foss/issues/41500 (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2018-20489?: CVE-2018-20489 is a medium-severity vulnerability in GitLab, classified under Improper Authentication. CVSS score: 5.3/10. Published 2019-12-30.
How severe is CVE-2018-20489?: Medium severity. CVSS v3 base score is 5.3 out of 10.