GitLab CE/EE Denial-of-Service Vulnerability via Malformed SSH Authentication Requests

A denial-of-service vulnerability has been addressed in GitLab Community Edition (CE) and Enterprise Edition (EE) versions 12.3 prior to 18.6.4, 18.7 prior to 18.7.2, and 18.8 prior to 18.8.2. The issue allowed an unauthenticated user to create a denial-of-service condition by sending repeated malformed SSH authentication requests, potentially overwhelming the server.

Impact

Exploitation of this vulnerability could lead to a denial-of-service condition, causing the GitLab instance to become unresponsive or slow down significantly.

Remediation

Users are advised to upgrade to GitLab versions 18.8.2, 18.7.2, or 18.6.4. Instructions for updating GitLab can be found on the GitLab Update page. For GitLab Runner, refer to the Updating the Runner page.