A security researcher has published some HTML code with CSS under the pseudonym @pwnsdx via Twitter, which turns into a kernel panic when called with iOS Safari leads. The iPhone or iPad then reboots.
The error affects every iOS device running iOS 7 or higher. Essentially, the few lines of CSS cause a blurring effect on every div element on the web page. The associated HTML of the page contains many div elements. Correspondingly much computing power is required.
The compute-intensive computation overloads the WebKit renderer and the system can only recover by kernel panic and restart.
If you want, you can of course test it yourself, but that's not necessary. Mac Life has tried it and lo and behold: even iOS 12 Golden Master crashes when called without singing and sound. The code is available on GitHub. Do not worry, calling the link will not cause a crash.
If you call the code on the desktop, it also causes a lot of memory to be allo- cated and the computer to be slow. However, we did not notice crashes under macOS and Windows.
There are always cases in which iOS devices crash through special characters in text messages, which is even more annoying in case of doubt, so when calling a website to record a crash. Theoretically, the HTML could also be embedded in an e-mail. We are curious if Apple responds to this and install a filter. Most likely, the fix will be incorporated into a future iOS update.