For GitLab before 13.0.12, 13.1.6, 13.2.3 a cross-site scripting vulnerability exists in the issues list via milestone title.
https://hackerone.com/reports/877065
https://gitlab.com/gitlab-org/gitlab/-/issues/218448
https://gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-13283.json