An issue was discovered in GitLab Community Edition and Enterprise Edition before 10.7.6, 10.8.x before 10.8.5, and 11.x before 11.0.1. The wiki contains a persistent XSS issue due to a lack of output encoding affecting a specific markdown feature.
https://gitlab.com/gitlab-org/gitlab-ce/issues/46957
https://about.gitlab.com/2018/06/25/security-release-gitlab-11-dot-0-dot-1-released/