GitLab has remediated an issue in GitLab CE/EE affecting all versions from 10.8 before 18.6.6, 18.7 before 18.7.4, and 18.8 before 18.8.4 that, under certain conditions, could have allowed an unauthenticated user to cause denial of service by sending repeated GraphQL queries.
Upgrade to versions 18.6.6, 18.7.4, 18.8.4 or above.