Cloudflare’s breakdown of the November 18 outage almost reads like one of those technical mishaps that grows quietly in the background until it finally breaks something big. Millions of people suddenly found themselves unable to access major sites including X, ChatGPT, Canva, and Discord. And while some early chatter hinted at the possibility of a cyber attack, Cloudflare clarified that the real culprit was a long-hidden internal bug that surfaced at the worst possible time.
Key Takeaways
- The November 18 outage stopped access to major sites like X, ChatGPT, and Canva for several hours.
- Cloudflare confirmed the cause was an internal software error, not a cyber attack.
- A routine update to a database accidentally made a configuration file too large for the system to process.
- Engineers fixed the issue by reverting the file and restarting affected systems.
- The company plans to strengthen its testing processes to prevent similar failures.
Things began to go sideways around 11:20 UTC when engineers made what seemed like a straightforward update to ClickHouse, the company’s database system. They were adjusting the way permissions were handled, which is the kind of thing you’d expect to be routine. Instead, that update caused a configuration file used to manage bot traffic to start duplicating itself. It kept expanding in the background, slowly pushing past a built-in limit the software wasn’t designed to exceed.
The system could only accommodate around 200 entries in that file. Once duplication pushed the count well past that threshold, the software struggled to read it and eventually crashed. The failure took place in a section of Rust code where the program is instructed to shut down completely if it encounters an error it cannot resolve. It’s the sort of scenario that feels almost theoretical until it actually happens.
Initially, Cloudflare’s team assumed they were dealing with a Distributed Denial of Service attack. The symptoms lined up closely enough that it wasn’t an unreasonable guess. But the normal traffic levels didn’t match that theory, so they kept digging. Eventually they traced the problem to their own security system repeatedly failing because of the bloated configuration file.
Once they identified the issue, engineers stopped the system from trying to load that file and swapped it out for a stable version. By around 14:30 UTC, most traffic began working again. Some smaller issues lingered, but those were completely resolved by 17:06 UTC. It’s interesting how the fix, once found, seemed almost simple compared to the confusion leading up to it.
For users, the outage showed up as HTTP 500 errors or odd messages asking them to unblock certain links. Because Cloudflare sits directly between websites and their visitors, its failures instantly block access, even when the sites themselves are operating normally. It’s something most people rarely think about until it suddenly stops working.
Cloudflare CEO Matthew Prince issued an apology, noting that the company had not experienced a failure anywhere near this scale in more than six years. He also said the incident made clear that their testing processes need another layer of protection. The company now plans to add checks that can detect oversized files before they reach live systems and to build faster kill switches so malfunctioning components can be disabled without affecting everything else.
All of this perhaps shows how a small, unnoticed bug can cause surprisingly large ripple effects across the internet. Even highly tested systems can still stumble in unexpected ways, and this outage was a reminder of how interconnected the web really is.
Frequently Asked Questions
Q. What caused the Cloudflare outage on November 18?
A. A routine database update caused a configuration file to grow too large. This file crashed the software that Cloudflare uses to manage web traffic.
Q. Was the outage caused by a cyber-attack?
A. No. Cloudflare confirmed that no malicious actors or cyber-attacks were involved. It was strictly an internal software error.
Q. Which websites did the outage affect?
A. The outage affected many major platforms, including X (Twitter), ChatGPT, Canva, Discord, and potentially any site that uses Cloudflare for security.
Q. How long did the internet outage last?
A. The problems began around 11:20 UTC. Engineers applied a primary fix by 14:30 UTC, and the company marked the incident as fully resolved by 17:06 UTC.
Q. What does “latent bug” mean in this context?
A. This refers to a software flaw that exists in the code but stays hidden until a specific set of conditions triggers it. In this case, the bug was the system’s inability to handle a file larger than a set limit.
