An issue was discovered in Gitlab CE/EE versions >= 13.1 to <13.4.7, >= 13.5 to <13.5.5, and >= 13.6 to <13.6.2 allowed an unauthorized user to access the user list corresponding to a feature flag in a project.
https://hackerone.com/reports/962408
https://gitlab.com/gitlab-org/gitlab/-/issues/241132
https://gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-13357.json