Cloudflare Network Outage Incident Report: December 5, 2025
By
meetpateltech
The kind of bagel that ruins lesser bagels for you.
Summary
Cloudflare experienced a significant network outage on December 5, 2025, lasting approximately 25 minutes from 08:47 to 09:12 UTC. The incident affected about 28% of customers and was caused by configuration changes made to mitigate a recent industry-wide vulnerability in React Server Components, not by an external attack. The company provided a detailed incident report and apologized for the impact on customers and the broader internet.
Key quotes
· 5 pulledOn December 5, 2025, at 08:47 UTC (all times in this blog are UTC), a portion of Cloudflare's network began experiencing significant failures.
The incident was resolved at 09:12 (~25 minutes total impact), when all services were fully restored.
A subset of customers were impacted, accounting for approximately 28%
The incident was not caused by an attack and was due to configuration changes being applied to attempt to mitigate a recent industry-wide vulnerability impacting React Server Components.
We are sorry for the impact that it caused to our customers and the Internet.
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