Cloudflare Outage Causes Global Internet Slowdown and Website Accessibility Issues

The Shocking Scale of Cloudflare’s Global Outage

On November 18, 2025, the internet experienced one of its most severe web service disruptions in recent years when Cloudflare, a major internet infrastructure provider, suffered a catastrophic global outage. The incident began at approximately 11:20 UTC, triggering widespread internet infrastructure outage effects that reverberated across digital platforms worldwide. According to NetBlocks director Alp Toker, the situation pointed to “a catastrophic disruption to Cloudflare’s infrastructure,” affecting thousands of websites simultaneously. The Cloudflare network issues impacted approximately 20% of global internet traffic, with users across six continents reporting website accessibility problems within minutes of the initial failure.

Unraveling the Chaos: How Major Websites Crumbled

The website accessibility problems resulting from the Cloudflare outage created immediate and visible disruption across popular online services. Users attempting to access affected sites were greeted with error messages indicating failures within Cloudflare’s network. Major platforms including X (formerly Twitter), Spotify, ChatGPT, and numerous e-commerce sites experienced significant CDN service interruption. The global internet slowdown was particularly pronounced for services heavily dependent on Cloudflare’s Bot Management system, which displayed HTTP 5xx error codes. Downdetector.com registered a massive spike in user reports beginning shortly after 7 a.m. ET, with some services experiencing complete inaccessibility for over two hours.

Cloudflare’s Race Against Time: Inside the Frantic Fix

Cloudflare engineers identified the root cause as an issue within their Bot Management module triggered by a configuration error. According to a detailed post-mortem by Cloudflare CEO Matthew Prince, the problem stemmed from “a change in underlying ClickHouse query behaviour that generates this file caused it to have a large number of duplicate ‘feature’ rows.” This changed the size of a previously fixed-size configuration file, causing the bots module to trigger an error. The company’s technical teams immediately mobilized to isolate the failing component and implement a solution, working frantically to restore normal service amid mounting pressure from affected customers experiencing website accessibility problems during the global internet slowdown.

Lessons Learned: Strengthening Internet Infrastructure for the Future

This Cloudflare network issues incident highlights critical vulnerabilities in modern internet architecture where centralized services create potential single points of failure. The web service disruption underscores the need for improved redundancy systems and more robust failover protocols within CDN providers. Industry experts note that while the number of service outages has remained consistent, the increasing dependency on cloud infrastructure magnifies their impact. Cisco ThousandEyes has documented 12 major outages in 2025 prior to this incident, indicating a concerning pattern of internet infrastructure outage events. Companies relying on third-party CDN services must develop comprehensive contingency plans to mitigate website accessibility problems during similar future disruptions.