Global Cloudflare Outage Disrupts Websites Worldwide

At 11:48 a.m. London time on Tuesday, 18 Nov 2025, Cloudflare reported a global service failure that produced error pages on sites, including X and OpenAI. The company traced the trigger to an automatically generated threat-traffic configuration file that grew beyond its expected size, causing a crash in the subsystem. By 2:48 p.m. London time a fix was applied and the incident was declared resolved, though Cloudflare warned of brief degradation as traffic rebounded.

The Guardian

Cloudflare provides DDoS mitigation, performance acceleration, API security, and the Warp encryption service for millions of websites, applications, and AI workloads. Its position as a “gatekeeper” of web traffic makes it a critical, though often invisible, component of the internet’s backbone.

The Guardian

The outage highlighted the concentration of essential internet services in a small number of providers. Downdetector recorded simultaneous disruptions for X and OpenAI, illustrating how a single point of failure can cascade across the web. Experts note that such incidents expose systemic risk and raise questions about redundancy in core online services.

The Guardian

Cloudflare apologized to its customers and to the internet in general, pledging to learn from the incident and improve. The firm confirmed that an oversized configuration file caused the crash and warned that services might experience brief degradation as traffic normalized. It also referenced a recent Amazon Web Services outage, highlighting reliance on a limited set of cloud platforms.

The Guardian

Prof. Alan Woodward, director of the Surrey Centre for Cyber Security, described Cloudflare as a largely unknown but influential company and warned that reliance on a few infrastructure providers makes failures immediately apparent. He emphasized that the scarcity of such gatekeepers means outages become highly visible and can threaten the stability of the broader internet ecosystem.

The Guardian

• “A fix has been implemented and we believe the incident is now resolved. We are continuing to monitor for errors to ensure all services are back to normal.” — Cloudflare, Official Statement

The Guardian

• “We will learn from today’s incident and improve.” — Cloudflare spokesperson

The Guardian

• “the biggest company you’ve never heard of” — Prof. Alan Woodward, Surrey Centre for Cyber Security

The Guardian

• “We’re seeing how few of these companies there are in the infrastructure of the internet, so that when one of them fails it becomes really obvious quickly,” — Prof. Alan Woodward, Surrey Centre for Cyber Security

The Guardian

Cloudflare will continue monitoring traffic as services normalize and has indicated that it will review the configuration-file generation process that triggered the crash. The company expects any remaining degradation to subside within hours, and the recent Amazon Web Services outage underscores scrutiny of reliance on a small set of cloud providers.

The Guardian