GitLab EE Improper Access Control Vulnerability in Runner API Allowing Project Runner Hijacking

A vulnerability exists in GitLab Enterprise Edition (EE) versions 17.1 prior to 18.3.5, 18.4 prior to 18.4.3, and 18.5 prior to 18.5.1. This vulnerability could have enabled an authenticated attacker with specific permissions to hijack project runners from other projects. The issue arises from improper access control in the runner API, allowing unauthorized manipulation of project runners.

Impact

Exploitation of this vulnerability could lead to unauthorized access and control over project runners, allowing attackers to execute jobs in the context of the hijacked runners.

Remediation

Users are advised to upgrade to GitLab versions 18.5.1, 18.4.3, or 18.3.5. Instructions for updating GitLab can be found on the GitLab Update page. For GitLab Runner, refer to the Updating the Runner page.