An information disclosure vulnerability in the GitLab CE/EE API since version 8.9.6 allows a user to see basic information on private groups that a public project has been shared with
https://hackerone.com/reports/538029
https://gitlab.com/gitlab-org/gitlab/-/issues/28226
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39905.json