Cloudflare Explains Global Internet Outage, Says Failure Came From Internal Network Bug
On Tuesday, 18 November 2025, millions of internet users across the world experienced service disruptions after a major Cloudflare outage briefly brought down some of the world’s biggest platforms including X, ChatGPT, Discord, Canva, and several high-traffic websites. Hours after restoring normal traffic flow, Cloudflare released a detailed explanation of what caused the widespread downtime. The company confirmed that the issue originated from an internal network bug, not from a cyber-attack or external interference.
What Happened?
According to Cloudflare, the outage began around 11:20 UTC when the company’s core traffic routing system started failing. This sudden breakdown triggered massive spikes in HTTP 5xx errors, preventing users from accessing websites and online services that depend on Cloudflare’s infrastructure.
Cloudflare engineers quickly began an investigation and narrowed the root cause to an unexpected failure inside one of their internal systems that supports the Bot Management feature. This system uses a “feature file,” a configuration file that feeds signals to machine-learning models used to identify and filter online bots.
The Technical Cause of the Outage
Cloudflare explained that a configuration change earlier in the day caused its database to produce duplicate entries, which led to the feature file becoming far larger than normal. When this bloated file propagated across Cloudflare’s global network, some of their core proxy services crashed because they weren’t designed to handle such a large configuration load.
In simple terms:
- A database change created too many signals in a bot-management file.
- This file was automatically sent across thousands of Cloudflare servers.
- The oversized file exceeded the system’s limits, causing critical proxy processes to fail.
- As these proxies crashed, many websites connected to Cloudflare became unreachable.
Cloudflare describe as an “internal software bug that triggered a cascading failure.”
Impact on the Internet
The outage affected:
- Content delivery
- Website security systems
- Authentication services
- Cloudflare dashboard logins
- API traffic
Several major platforms relying on Cloudflare for uptime
The downtime lasted nearly three hours, with Cloudflare confirming full resolution by 17:06 UTC.
This outage was one of the most significant Cloudflare incidents since 2019, affecting millions of end-users and businesses worldwide.
Cloudflare’s Fix and Preventive Measures
After identifying the issue, Cloudflare engineers:
- Stopped the faulty file from updating
- Rolled back to a stable configuration
- Restarted impacted services
- Performed global health checks
- Restored normal traffic gradually
The company also announced several steps to prevent similar outages in the future, including:
- Stricter validation of configuration files
- More robust error-handling in their proxy system
- Additional kill-switches to disable problematic features quickly
- Improved monitoring and crash-prevention systems
Cloudflare emphasized that no customer data was compromised, and the incident was not related to hacking or a DDoS attack.
Why This Matters
Cloudflare powers a large portion of the world’s internet traffic. When its systems fail, the impact is immediate and global. The incident highlights the challenges of operating massive, interconnected internet infrastructure — where even a small internal bug can create worldwide disruptions.
For website owners, developers, and online businesses, it’s a reminder of:
- The importance of uptime monitoring
- Preparing for dependency-related outages
- Understanding how third-party infrastructure affects your website’s performance
Conclusion
Cloudflare’s transparency in explaining the failure provides valuable insight into how complex and sensitive global internet infrastructure can be. While the company restored services quickly, the outage demonstrates how a minor internal bug can ripple across the world, affecting millions of users and major platforms within minutes.
