CVE-2020-26409

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-12-11 · updated 2026-06-17
Weakness: CWE-20

Description

A DOS vulnerability exists in Gitlab CE/EE >=10.3, <13.4.7,>=13.5, <13.5.5,>=13.6, <13.6.2 that allows an attacker to trigger uncontrolled resource by bypassing input validation in markdown fields.

Affected products

GitLab: from 10.3.0 before 13.4.7; from 13.5.0 before 13.5.5; from 13.6.0 before 13.6.2 — fixed in 13.4.7, 13.5.5, 13.6.2

How to fix

Upgrade to a fixed version: GitLab 13.4.7, 13.5.5, 13.6.2. Check the vendor advisory for mitigations.

References

https://gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-26409.json
https://gitlab.com/gitlab-org/gitlab/-/issues/259626
https://hackerone.com/reports/990461
https://gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-26409.json
https://gitlab.com/gitlab-org/gitlab/-/issues/259626
https://hackerone.com/reports/990461

Get alerted when CVE-2020-26409 or the next vulnerability affects your stack