GitLab CE/EE Server-Side Request Forgery Vulnerability in Webhook Custom Header

A server-side request forgery (SSRF) vulnerability has been identified in GitLab Community Edition (CE) and Enterprise Edition (EE) versions 16.11 prior to 18.1.6, 18.2 prior to 18.2.6, and 18.3 prior to 18.3.2. This vulnerability could have allowed authenticated users to make unintended internal requests through proxy environments by injecting crafted sequences.

Impact

Exploitation of this vulnerability could have led to unauthorized internal requests being made, potentially allowing for further exploitation or information disclosure.

Remediation

Users are advised to upgrade to GitLab versions 18.3.2, 18.2.6, or 18.1.6. Instructions for updating GitLab can be found in the GitLab Update documentation. For GitLab Runner, refer to the Updating the Runner page.