How a single line of code caused the internet to crash? Cloudflare failure and global outage

Can a single line of code really cause the internet to crash? Normally, when you visit a website, your browser sends a request to a server, and the server returns the necessary data. But the process is not that simple. If a website is hit by a DDOS attack, millions of simultaneous requests overload the system and cause it to stop responding. In other cases, bots silently scrape and attempt to steal data. This is exactly why websites use services like Cloudflare.

With Cloudflare, a protective layer stands between you and the website. Your request is analyzed, and if there are signs of an attack, it is blocked. Additionally, Cloudflare improves speed optimization by storing popular pages across global CDN servers and directing users to the closest location. This results in faster loading times.

But what happens if this intermediate layer crashes? In that case, the main website becomes unreachable. This is exactly what happened recently, and a large portion of the internet went offline. Surprisingly, the cause was just one line of code.

Inside Cloudflare, there is a special bot detection system that updates every 5 minutes and analyzes around 60 parameters to identify bots. This allows even newly created bots to be detected continuously. The system was developed in the Rust programming language and included a memory upper limit. It allocated memory for a maximum of 200 parameters, improving performance and reducing RAM allocation overhead.

The real issue came from the Rust unwrap operator. If a value exists, unwrap returns it, but if not, it triggers panic and crashes the process. The value in this case was expected to never be empty. However, after the latest update, more than 200 parameters began arriving. When the limit was exceeded, unwrap triggered a panic and the system failed. Users attempting to access websites were met with a temporary server error message and instructed to try again.

This incident affected major platforms such as X (Twitter), Visa and ChatGPT, as well as many other international services. At the same time, several banks, government institutions and private organizations operating in Azerbaijan also experienced temporary inaccessibility and connectivity issues on their websites. The cause of this widespread interruption across different parts of the internet was nothing more than a single line of code.