In GitLab before 13.0.12, 13.1.6 and 13.2.3, access grants were not revoked when a user revoked access to an application.
https://hackerone.com/reports/469728
https://gitlab.com/gitlab-org/gitlab/-/issues/26147
https://gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-13294.json