A race condition in GitHub Enterprise Server allowed an existing admin to maintain permissions on a detached repository by making a GraphQL mutation to alter repository permissions while the repository is detached. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.13 and was fixed in versions 3.9.13, 3.10.10, 3.11.8 and 3.12.1. This vulnerability was reported via the GitHub Bug Bounty program.