An out-of-bounds read vulnerability was identified in GitHub Enterprise Server in the Git service (babeld). When proving possession of a host key, babeld's SSH implementation sized the session identifier by the current digest length rather than its own. An attacker with an account and SSH access could re-key to an algorithm with a longer hash, causing adjacent process memory to be signed and returned to the client, where a limited amount of it may be recoverable. This vulnerability affected all releases prior to 3.23 and was fixed in versions 3.22.3, 3.21.8, 3.20.10, and 3.19.14. This vulnerability was reported via the GitHub Bug Bounty program.