A security researcher has found a new way to crash and restart any iPhone — with just a few lines of code.

Sabri Haddouche tweeted a proof-of-concept webpage with just 15 lines of code which, if visited, will crash and restart an iPhone or iPad. Those on macOS may also see Safari freeze when opening the link.

The code exploits a weakness in iOS’ web rendering engine WebKit, which Apple mandates all apps and browsers use, Haddouche told TechCrunch. He explained that nesting a ton of elements — such as <div> tags — inside a backdrop filter property in CSS, you can use up all of the device’s resources and cause a kernel panic, which shuts down and restarts the operating system to prevent damage.

“Anything that renders HTML on iOS is affected,” he said. That means anyone sending you a link on Facebook or Twitter, or if any webpage you visit includes the code, or anyone sending you an email, he warned.