An authorization issue relating to project maintainer impersonation was identified in GitLab EE 9.5 and later through 13.0.1 that could allow unauthorized users to impersonate as a maintainer to perform limited actions.
Client-Side code injection through Mermaid markup in GitLab CE/EE 12.9 and later through 13.0.1 allows a specially crafted Mermaid payload to PUT requests on behalf of other users via clicking on a link
A security issue allowed achieving Denial of Service attacks through memory exhaustion by uploading malicious artifacts in all previous GitLab versions through 13.0.1