GitLab CE/EE Denial-of-Service Vulnerability in Markdown Processing

A denial-of-service vulnerability has been identified in GitLab Community Edition (CE) and Enterprise Edition (EE) versions 16.9 prior to 18.3.6, 18.4 prior to 18.4.4, and 18.5 prior to 18.5.2. This vulnerability allows an authenticated attacker to disrupt service by submitting specially crafted markdown content that includes nested formatting patterns.

Impact

Exploitation of this vulnerability leads to a denial-of-service condition, causing disruptions in service availability.

Remediation

Users are advised to upgrade to GitLab versions 18.5.2, 18.4.4, or 18.3.6. Instructions for updating GitLab can be found on the GitLab Update page. For GitLab Runner, refer to the Updating the Runner page.