What is CVE-2020-26407?

CVE-2020-26407 is a medium-severity vulnerability in GitLab, classified under Cross-site Scripting. CVSS score: 5.5/10. Published 2020-12-10.

How severe is CVE-2020-26407?

Medium severity. CVSS v3 base score is 5.5 out of 10.

XSS in GitLab

CVE-2020-26407

A XSS vulnerability exists in Gitlab CE/EE from 12.4 before 13.4.7, 13.5 before 13.5.5, and 13.6 before 13.6.2 that allows an attacker to perform cross-site scripting to other users via importing a malicious project

Vulnerability class: XSS (Cross-Site Scripting)

Published 2020-12-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.007 (52.5th percentile), scored 2026-10-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 52.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: +0.000

Affected products

GitLab
GitLab Ce/ee — versions >=12.4, <13.4.7, >=13.5

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

gitlab.com/gitlab-org/gitlab/-/issues/212630 (Broken Link)
hackerone.com/reports/832117 (Permissions Required, Third Party Advisory)
gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-26407.json (Third Party Advisory)

Frequently asked questions

What is CVE-2020-26407?: CVE-2020-26407 is a medium-severity vulnerability in GitLab, classified under Cross-site Scripting. CVSS score: 5.5/10. Published 2020-12-10.
How severe is CVE-2020-26407?: Medium severity. CVSS v3 base score is 5.5 out of 10.