Reasons for the Cloudflare failure that took down a third of the internet
14:49, 20.11.2025
Actually, the failure of many internet resources was caused by a single misconfigured file. This is yet another clear demonstration of the negative impact that centralization of digital resources can have. Cloudflare is one of the largest CDN providers, with a 28% market share. Therefore, failures in Cloudflare's infrastructure affect a third of the internet.
Cloudflare system failure
On November 18, a significant failure occurred in Cloudflare, resulting in the unavailability of certain McDonald's branches, OpenAI services, and numerous other resources.
The company's co-founder, Matthew Prince, explained the reasons for the failure in detail. The situation occurred due to changes in database permissions, which resulted in several records being output to the “function file.” As a result, the function file doubled in size and was distributed to all machines on the network.
After the file that caused the error was deployed, it continued to spread throughout the infrastructure for some time, gradually affecting the network. After approximately 3 hours, the problem was detected and fixed, and after 6 hours, all affected systems were restarted and returned to the norm.