Disruption with Login and Release Asset downloads
This summary is created by Generative AI and may differ from the actual content.
Overview
On August 12 and 13, 2026, anonymous (logged-out) requests to github.com experienced HTTP 5xx errors when loading pages like the sign-in page and when downloading release assets. Three windows of impact occurred: August 12 from 16:34 to 18:34 UTC with average error rate of 16.16% peaking at 28.6%, August 12 from 19:00 to 22:56 UTC with average error rate of 16.55% peaking at 24.18%, and August 13 from 06:19 to 08:05 UTC with average error rate of 2.01% peaking at 7.49%. Requests from signed-in users were unaffected. The incidents were caused by an unusual traffic pattern that repeatedly overloaded infrastructure serving anonymous requests. Mitigation was applied through traffic controls at the network edge to limit requests matching the identified pattern.
Impact
Significant impact on anonymous users accessing GitHub's sign-in page and release asset downloads across three separate windows totaling approximately 7 hours. Error rates ranged from 2.01% to 16.55% average with peaks up to 28.6%. Signed-in users experienced no impact.
Trigger
An unusual traffic pattern that repeatedly overloaded the infrastructure serving anonymous (logged-out) requests to github.com.
Detection
Monitoring systems detected elevated HTTP 5xx error rates affecting logged-out traffic. Investigation was initiated at 21:39 UTC on August 12, 2026, when the first status update indicated reports of impacted performance were being investigated.
Resolution
Traffic controls were applied at the network edge to limit requests matching the identified unusual traffic pattern, thereby preventing overload on the affected infrastructure. Monitoring systems were tightened to alert on server-side errors affecting logged-out traffic. Edge protections are being strengthened to reduce detection and mitigation time for similar incidents.
Root Cause
An unusual traffic pattern that repeatedly overloaded the infrastructure serving anonymous requests. The specific nature of the traffic pattern was identified but not detailed in the postmortem.