Intermittent authentication failures on GitHub

Final update

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 a

1. Resolved · Feb 17, 19:06 UTC
   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.