An issue was discovered in GitLab Enterprise Edition before 11.1.7, 11.2.x before 11.2.4, and 11.3.x before 11.3.1. Attackers could obtain sensitive information about group names, avatars, LDAP settings, and descriptions via an insecure direct object reference to the "merge request approvals" feature.
https://about.gitlab.com/releases/2018/10/01/security-release-gitlab-11-dot-3-dot-1-released/