Intermittent authentication failures on GitHub
Incident
Report for GitHub
Resolved
On February 17, 2026, between 17:07 UTC and 19:06 UTC, some customers experienced intermittent authentication failures affecting GitHub Actions, parts of Git operations, and other authentication-dependent requests. On average, the Actions error rate was approximately 0.6% of affected API requests. Git operations ssh read error rate was approximately 0.29%, while ssh write and http operations were not impacted. During the incident, a subset of requests failed due to token verification lookups intermittently failing, leading to 401 errors and degraded reliability for impacted workflows.
The issue was caused by elevated replication lag in the token verification database cluster. In the days leading up to the incident, the token store’s write volume grew enough to exceed the cluster’s available capacity. Under peak load, older replica hosts were unable to keep up, replica lag increased, and some token lookups became inconsistent, resulting in intermittent authentication failures.
We mitigated the incident by adjusting the database replica topology to route reads away from lagging replicas and by adding/bringing additional replica capacity online. Service health improved progressively after the change, with GitHub Actions recovering by ~19:00 UTC and the incident resolved at 19:06 UTC.
We are working to prevent recurrence by improving the resilience and scalability of our underlying token verification data stores to better handle continued growth.
The issue was caused by elevated replication lag in the token verification database cluster. In the days leading up to the incident, the token store’s write volume grew enough to exceed the cluster’s available capacity. Under peak load, older replica hosts were unable to keep up, replica lag increased, and some token lookups became inconsistent, resulting in intermittent authentication failures.
We mitigated the incident by adjusting the database replica topology to route reads away from lagging replicas and by adding/bringing additional replica capacity online. Service health improved progressively after the change, with GitHub Actions recovering by ~19:00 UTC and the incident resolved at 19:06 UTC.
We are working to prevent recurrence by improving the resilience and scalability of our underlying token verification data stores to better handle continued growth.
Update
We are continuing to monitor the mitigation and continuing to see signs of recovery.
Update
We have rolled out a mitigation and are seeing signs of recovery and are continuing to monitor.
Update
We have identified a low rate of authentication failures affecting GitHub App server to server tokens, GitHub Actions authentication tokens, and git operations. Some customers may experience intermittent API request failures when using these tokens. We believe we've identified the cause and are working to mitigate impact.
Investigating
We are investigating reports of degraded performance for Actions and Git Operations
This incident affected: Git Operations and Actions.
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