2026-06-23: git pushes are failing via ssh

git pushes are failing via ssh (Severity 1)

Problem: Git operations over SSH failed for many users due to authentication errors, preventing repository access.

Impact: Git operations over SSH failed globally during the outage.

Causes:

GitLab Shell is the SSH gateway for GitLab — it handles incoming SSH connections (via its own SSH daemon, gitlab-sshd), authenticates users against the GitLab Rails internal API, and then proxies git operations to Gitaly over gRPC.

This incident was triggered by a configuration change that made an existing TLS secret available to gitlab-shell. Along with adding the TLS secret, the change also enabled the topology service for gitlab-shell. Enabling the topology service activated new routing logic for /allowed requests, which gitlab-shell uses to authorize SSH operations. This routing logic had not been validated in the GitLab.com environment, where the topology service returned a cell address that was not valid as an internal API endpoint.

Response strategy: We reverted the configuration that enabled the Topology Service for GitLab Shell and rolled out the fix across all zones. SSH and HTTPS access to repositories has been restored and we are monitoring for further issues.

This ticket was created to track INC-11437, by incident.io 🔥