Cloudflare was down — here’s what caused the outage that took out 20% of all websites

Things seem to be back to normal

Down Detector reports have dropped back down super low, and in our tests, no more 500 server errors are appearing on any sites that are on the Cloudflare side of things.

We’ll keep monitoring the situation in the background, and will be waiting for Cloudflare’s blog explaining what happened here.

Cloudflare CTO Dane Knecht posted on X about the issues internet users saw. Let’s break it down.

So the good news is it wasn’t a hostile cyberattack like a DDoS. Cloudflare was attempting to fix a security vulnerability (known as Common Vulnerabilities and Exposures (CVE)) in the web dev framework Cloudflare uses called React.

Full details will be shared in a blog explainer later today.

So the Cloudflare status page initially showed this, then stopped loading. Now that the page is back up, we’re not seeing this at all. Instead, we’re seeing updates about “scheduled maintenance” happening today at the DTW (Detroit) and ORD (Chicago) locations.

On top of this, some Workers scripts issues too.

You can see how many services have been impacted by this. Quick side note: AWS is not down. Their status page shows all servers running normally. Cloudflare is a different entity.