A vulnerability was discovered in GitLab versions before 13.1.10, 13.2.8 and 13.3.4. GitLab was vulnerable to a blind SSRF attack through the repository mirroring feature.
https://hackerone.com/reports/860196
https://gitlab.com/gitlab-org/gitlab/-/issues/215879
https://gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-13309.json