On May 28, 2026, between 00:54 UTC and 01:19 UTC, some users experienced errors when interacting with the Webhooks API, including webhook delivery history and configuration endpoints. On average, the error rate was 0.28% and peaked at 0.45%. This was due to a bug that caused a single Kubernetes pod to enter a CrashLoopBackOff after receiving a 500 with an empty response body from Cosmos DB.We mitigated the incident by restarting the service. To prevent future incidents, we are pushing a change to handle this response scenario from Cosmos DB appropriately.
On May 27, 2026, between 12:07 UTC and 13:16 UTC, users experienced degraded performance for Git operations, Pull Requests, Issues, GraphQL API, and related services on github.com. During this time, operations that depended on Git file servers experienced elevated error rates (3.5% of pushes via HTTPS and 0.2% of pushes via SSH failed; no fetches/clones failed). An internal analytics component generated unexpectedly high load, which caused CPU saturation on the underlying infrastructure. This led to cascading slowdowns and errors across services that depend on Git operations. The issue was mitigated by stopping the offending component. Services began recovering shortly after mitigation and were fully restored by 13:16 UTC. We are taking steps to add resource limits and kill switches for internal analytics components to prevent similar issues in the future.
On May 26, 2026, between 15:10 UTC and 16:35 UTC the Copilot service was degraded and many models were no longer available for use. On average, the error rate was ~5% and peaked at 11% of requests to the service. This was due to a change that introduced a configuration mismatch in HMAC signing credentials which caused the list of available models to be truncated. This was mitigated by rolling back the change. This rollback was complete by 15:34 UTC though users continued to see impact until cache TTLs expired. We are working to improve our monitoring and error handling to reduce time to detection and better experience for issues like this in the future.
On May 26, 2026, between 10:40 UTC and 12:56 UTC, GitHub Actions jobs were degraded. From 10:40 to 12:16 UTC, all newly queued Actions runs failed to start. From 12:16 to 12:56 UTC, Actions runs that required downloading actions for their workflows continued to fail. GitHub Pages, Copilot Code Review, Copilot coding agent, Octoshift, and GitHub Enterprise Importer were also impacted due to their dependency on Actions. This was caused by our automated account review system incorrectly suspending the service account used by GitHub Actions to authenticate workflow runs and download actions. We mitigated by restoring the account at 12:16 UTC, marking it exempt from further automated review at 12:20 UTC, and redeploying a related service at 12:48 UTC to flush cached account state. Full recovery was confirmed at 12:56 UTC. During this incident, a small number of Issues, PRs, Comments, and Discussions were marked as hidden when the service account was disabled. No data was lost. All content hidden because of this incident has been restored and full search index restoration is in progress. To prevent a recurrence, we have added an allowlist of all service accounts that cannot be suspended by automated systems, and ensuring these protections are enforced consistently across all account management tooling. We are also improving diagnostic tooling for accounts and reducing cache propagation delays to shorten time to mitigate similar incidents in the future.
On May 23, 2026 between 06:00 UTC and 19:12 UTC, GitHub experienced intermittent errors authenticating GitHub app installation tokens.
During this time, between 1-5% of app installation token authentication requests failed, with an average of 2.3% and the error rate peaking at approximately 5.4% around 14:00 UTC. Users may have experienced authentication failures when using GitHub Apps, including failures in Git operations and API calls using app installation tokens.
The issue was caused by an issue in a caching proxy component and was remediated by rolling back that component to a previous version. We are taking steps to improve monitoring for cache miss anomalies to ensure that token authentication remains functional during infrastructure changes and reviewing our protocol for testing and when we upgrade third-party dependencies.
On May 20, 2026, between 16:00 UTC and 17:45 UTC, GitHub Actions customers experienced run start delays exceeding 5 minutes. Approximately 4.5% of all runs were delayed during the impact window, with scale set jobs disproportionately affected. 30% of scale set jobs were delayed and 4% failed to start entirely. The incident was caused by a misconfigured health check on an internal service that assigns jobs to runners. A brief latency spike in an upstream dependency triggered health check failures across several pods, removing them from service and concentrating load on the remaining capacity. The added load drove memory pressure that escalated into a cascading failure in one regional cluster, leaving it unable to self-recover. Responders mitigated the incident by scaling capacity in the healthy regional clusters and draining traffic away from the impaired one, after which run start latency recovered. To prevent recurrence, we are strengthening our health check configuration to avoid cascading failure scenarios and evaluating automated mitigations to rebalance traffic when a region is degraded.
On May 15, 2026, from approximately 07:43 UTC to 08:48 UTC, GitHub Actions experienced a degradation that caused workflow runs to fail or experience delayed starts for a subset of customers. The incident was triggered by a planned failover of supporting infrastructure used by GitHub Actions. During that operation, an automated service discovery update did not propagate correctly, which caused traffic to be routed incorrectly and increased request timeouts in a core dependency for workflow orchestration. At peak impact, 42% of Actions runs failed. Downstream services that depend on Actions workflow execution were also impacted, including GitHub Pages and Copilot cloud services. At 08:12 UTC, responders manually corrected the service discovery routing issue. Timeout and failure rates recovered shortly after, and we continued monitoring until full stabilization was confirmed across all affected services. The incident was marked resolved at 08:48 UTC. To prevent recurrence, we are implementing failover guardrails that validate service discovery state before completing failover operations, strengthening pre-flight and post-flight verification checks, and improving dependency resilience to reduce timeout cascades during infrastructure events.
Beginning at 02:49 UTC on May 15 2026 and lasting until 03:04 UTC, GitHub.com was unavailable for a subset of customers. This impact has been mitigated and normal service resumed.
The issue was rooted in a sudden spike in traffic, with intermittent impact. We've identified the source of the traffic and prevented further disruption.
On May 13, 2026, between 14:31 and 16:03 UTC, the Code Scanning service experienced processing delays and 12% of check runs took over 15 minutes to complete. The delays were caused by replication lag due to an internal database migration, resulting in insufficient worker capacity for our high rate of job enqueues. We mitigated the impact by scaling our processing workers by 34%. Code Scanning results returned to normal processing times after the mitigation was applied. The capacity increases are permanent, and we are looking into more ways to decrease the load on our workers to help prevent this in the future.
On May 12, 2026, between 13:41 and 17:43 UTC, some services experienced delays in processing. For the Code Scanning service, 53% of check runs took over 15 minutes to complete. Additionally, notifications took an average of 22 minutes to be delivered and Slack integration webhooks took an average of 20 minutes to be delivered. The delays were caused by replication lag due to an internal database migration, resulting in insufficient worker capacity for our high rate of job enqueues. We mitigated the impact by scaling our processing workers to handle the increased load. All services returned to normal processing times after the mitigation was applied. We are working to create dedicated worker pools for some of our high usage shared queues to help prevent this in the future.