Cloudflare outage explained: What is 'latent bug' that took the internet down, what company said

Cloudflare outage brought down hundreds of websites across the globe. Websites across the web crashed after what Cloudflare describes as a 'spike in unusual traffic.' The almost six-hour-long outage was caused by a latent bug. San Francisco-based Cloudflare provides the infrastructure and security for many websites worldwide. One of the company’s main areas of service is protecting websites against distributed denial-of-service (DDoS) attacks, which occur when multiple bad actors flood a website or network with traffic requests to overload it and degrade performance or cut off access.

Some of the biggest websites that went down include ChatGPT, Twitter, Perplexity, Claude and also the outage-tracking site DownDetector. Other online services, including Grindr, Uber, Canva, Spotify, NJ Transit and League of Legends also experienced issues during the outage.

What Cloudflare said on the outage

The cause of the outage was a configuration file that is automatically generated to manage threat traffic, Jackie Dutton, a Cloudflare spokesperson said in a statement. There was no evidence of a cyberattack or malicious activity, the statement said. “The file grew beyond an expected size of entries and triggered a crash in the software system that handles traffic for a number of Cloudflare’s services,” said Dutton.

"In short, a latent bug in a service underpinning our bot mitigation capability started to crash after a routine configuration change we made. That cascaded into a broad degradation to our network and other services. This was not an attack,” Knecht wrote, referring to a bug that goes undetected in testing and has not caused a failure," Cloudflare's chief technology officer Dane Knecht wrote on Twitter.

Cloudflare down error message

Some sites displayed the error message, “Please unblock challenges.cloudflare.com to proceed.”

What experts said on the outage

Explaining Cloudflare outage, information technology professor at the University of Notre Dame’s Mendoza College of Business, Mike Chapple, said that Cloudflare works behind the scenes to make the internet faster and safer, but when problems flare up “it results in massive digital gridlock” for internet users. Chapple further added that Cloudflare is a “content delivery network” that takes content from 20% of the world’s websites and mirrors them on thousands of servers worldwide.

“When you access a website protected by Cloudflare, your computer doesn’t connect directly to that site,” Chapple said. “Instead, it connects to the nearest Cloudflare server, which might be very close to your home. That protects the website from a flood of traffic, and it provides you with a faster response. It’s a win-win for everyone, until it fails, and 20% of the internet goes down at the same time.”

Cloudflare fixes outage

After hours of disruption, Cloudflare announced that the issues has been resolved. The company also posted an update saying:

Cloudflare services are currently operating normally. We are no longer observing elevated errors or latency across the network.Our engineering teams continue to closely monitor the platform and perform a deeper investigation into the earlier disruption, but no configuration changes are being made at this time.At this point, it is considered safe to re-enable any Cloudflare services that were temporarily disabled during the incident. We will provide a final update once our investigation is complete.