Between 15:05 UTC and 16:25 UTC, GitHub API services experienced degraded availability due to sporadic authentication failures affecting approximately 9% of requests. Customers experienced intermittent "logged out" behavior as erroneous 401 responses triggered repeated authentication flows in app integrations. Affected requests also experienced approximately 800ms of additional latency. A memcached proxy service rollout to our internal API infrastructure caused our authentication service to pick up an incorrect memcached host configuration, leading to intermittent authentication lookup failures. We mitigated the incident by deploying a configuration change to memcached to use the correct host. To prevent similar issues in the future, we plan to migrate our authentication system to the new memcached infrastructure to improve resilience and strengthen overall reliability posture.
On June 8, 2026, between 14:49 and 14:54 UTC, a subset of requests to GitHub.com, the REST API, GraphQL API, and Webhooks UI/API experienced elevated error rates due to a transient infrastructure capacity issue that self-resolved within approximately 5 minutes.
Users experienced HTTP 500 errors and timeouts when accessing GitHub.com, the REST API, GraphQL API, and Webhooks UI/API for approximately 5 minutes, with the REST API taking up to 12 minutes to fully recover.
On May 25, 2026, between 09:02 UTC and 09:11 UTC, Git push operations over HTTPS and SSH experienced elevated failures. During this window, an average of 31% and a peak of 43% of push requests failed.
The incident was caused by a recently enabled code path that issued an unexpectedly expensive database query against a primary database. The resulting load exhausted the database's connection pool, which caused the push failures above. The acute impact resolved automatically as in-flight work completed. We mitigated the incident by disabling the feature flag controlling the new code path. To prevent recurrence, we have updated the affected background workflows to route reads to replica databases instead of the primary, removing the specific code pattern that caused this incident; broader follow-up work is underway to apply the same safeguard to similar workflows across GitHub.
On June 8, 2026, between 08:40 UTC and 09:30 UTC, the Claude Opus 4.7 model experienced degraded availability with error rates peaking at 8.4% and averaging 1.9%. This was due to an upstream provider issue that caused temporary unavailability and rate limiting on secondary failover systems. Users selecting Auto or alternative models were unaffected. We are improving provider failover mechanisms and monitoring to prevent similar issues.
On June 8, 2026, between approximately 06:30 UTC and 08:36 UTC, signed-out users experienced sustained elevated HTTP 504 errors when accessing Pull Requests, Issues, releases, patch diffs, and other related GitHub.com pages. During the incident, approximately 17% of unauthenticated requests to the affected GitHub.com endpoints returned gateway timeout errors, peaking at roughly 34% of requests at around 06:50 UTC. Some GitHub Actions workflows were also affected when they depended on release downloads or related GitHub.com endpoints. The impact lasted approximately two hours and was isolated to unauthenticated traffic; signed-in users were not affected. The issue was caused by a significant increase in abusive traffic to specific GitHub.com endpoints. This degraded our ability to respond to unauthenticated requests, causing requests to queue beyond timeout thresholds and return gateway timeout errors. We mitigated the incident by identifying the anomalous traffic pattern and applying targeted blocks at the load balancer and application layers. Error rates returned to normal and affected services were fully restored by 08:36 UTC. To reduce the likelihood and impact of similar incidents in the future, we are improving automated detection and blocking for these traffic patterns, improving our emergency traffic-blocking deployment path, and evaluating routing changes for endpoints used by both signed-out users and automated workflows.
On June 6, 2026 between 16:18 UTC and 17:01 UTC, users experienced elevated error rates when performing Git operations (cloning, fetching, downloading archives) and accessing package registries. The issue affected users whose traffic was routed through our European infrastructure.During this time, on average 0.95% of Codeload requests and 9.2% of Package Registry requests failed with server errors. At peak, the Codeload error rate reached 1.76% and Package Registry errors reached 27%.The root cause was a planned network circuit migration that disrupted connectivity at one of our points of presence. Our process for shifting traffic away from the site did not operate as expected, resulting in a small amount of production traffic to continue being serviced at the effected site during the maintenance window. The issue was mitigated by rolling back the network change, restoring normal connectivity. Services fully recovered by 17:01 UTC.To reduce the likelihood of similar incidents in the future, we are reviewing our site drain process to make it more verbose and add visibility so any unexpected behavior is caught earlier.
This incident was used to notify for a maintenance event. There is no specific root cause analysis. Maintenance did run longer than expected (we were complete at 18:48 UTC) but the work proceeded as planned.
On June 5, 2026, between 15:35 UTC and 16:45 UTC, 0.11% of authenticated REST API requests incorrectly returned “not found” responses. Impact was concentrated among - and significantly higher for - users authenticating with user-to-server tokens to access organization-owned repositories.Some users of our GitHub for Slack and GitHub for Microsoft Teams integrations saw their channel subscriptions removed as those systems interpreted the transient "not found" response as durable loss of access. Roughly 12% of organizations with active channel subscriptions were impacted, with ~2% of all channel subscriptions being removed.These issues were triggered by a change to an internal authorization component that did not correctly resolve access for user-to-server tokens against organization-owned repositories. We mitigated the incident by disabling the accompanying feature flag at 16:45 UTC, after which API responses returned to normal. We then restored all impacted Slack and Microsoft Teams channel subscriptions, with restoration completed at 22:21 UTC.We are working to add retry and grace-period logic in the chat integrations so transient errors no longer trigger subscription deletions. In parallel, we are improving observability and gating of authorization changes so downstream impact is detected during scoped, gradual rollouts.
On June 4, 2026, from 17:30 UTC to 18:55 UTC, Copilot Code Review experienced elevated failures for review requests on GitHub.com. Affected users saw “Copilot ran into an error” on pull requests when requesting a code review.During the incident window, an average of 81.6% of Copilot Code Review requests failed, with a peak failure rate of 93.9%. Approximately 36,800 code review requests failed. GitHub Enterprise Cloud with data residency was not impacted.The issue was caused by a newly released dependency used by the Copilot Code Review processing workflow. The release introduced an incompatibility with the runtime environment. Because the workflow automatically consumed the latest release, the incompatible version was picked up without sufficient compatibility validation and caused review processing to fail.We mitigated the incident by removing the problematic dependency version and redeploying the affected processing service. New code reviews began recovering at 18:44 UTC, and the failure rate returned to baseline by 18:55 UTC. Remaining timed-out work drained by 19:59 UTC.To reduce the risk of recurrence, we are pinning the dependency version instead of automatically consuming the latest release, adding compatibility checks for future releases, improving fast-failure behavior when the review processor cannot start, adding shorter timeout controls for review workflows, and improving monitoring for review completion failures.