An Open Redirect issue was discovered in GitLab Community and Enterprise Edition before 11.7.8, 11.8.x before 11.8.4, and 11.9.x before 11.9.2. A redirect is triggered after successful authentication within the Oauth/:GeoAuthController for the secondary Geo node.
https://gitlab.com/gitlab-org/gitlab-ee/issues/9731
https://about.gitlab.com/blog/categories/releases/
https://about.gitlab.com/2019/04/01/security-release-gitlab-11-dot-9-dot-4-released/