A privilege escalation issue was discovered in GitLab CE/EE 9.0 and later when trigger tokens are not rotated once ownership of them has changed.
https://hackerone.com/reports/495282
https://gitlab.com/gitlab-org/gitlab-ce/issues/58312
https://about.gitlab.com/releases/2019/07/29/security-release-gitlab-12-dot-1-dot-2-released/