There seems to be a newly discovered bug which causes Messages on iOS to crash when the following text is received. It can also cause the iPhone to reboot. Dubbed #effectivepower on Twitter, you simply copy the following text (with line breaks) and send it in a message to an iPhone user.
Ù„ÙÙ„ÙØµÙ‘Ø¨ÙÙ„ÙÙ„ØµÙ‘Ø¨ÙØ±Ø±Ù‹ à¥£ à¥£h à¥£ à¥£
I can tell you it is due to how the banner notifications process the Unicode text. The banner briefly attempts to present the incoming text and then “gives up” thus the crash. On a jailbroken device, this ultimately leads to safe mode. However, on a stock iOS device, there is no safe mode hence the respring after the crash. That is why this only happens when you are not in the message because the banner is what truly crashes the entire system. Is this a possible vulnerability? Maybe. Has this been around already? Roughly since iOS 6. Can it be fixed/patched? That, my friends, is up to Apple. I hope I cleared things up a little bit if it did help in anyway, shape, or form.
This also works from any device it is sent from, too. Whether it is Android, Windows Phone or an iPhone itself. To resolve the crashing, you can simply get the person who sent the malicious message to send another message which will cancel out the initial one. The other option is to use Siri, your Mac, share sheet, or send a photo to the person from Photos app who sent the malicious text.