UPDATE – MacTrast scribe Ian Fuchs reports the bug also causes Springboard on the Apple Watch to crash, as seen in his video, shown below. He has also observed that the bug doesn’t seem to affect devices running iOS 7.
A new bug has been discovered in the iOS Messages app that causes an iPhone to crash and reboot when it receives a message with a specific string of symbols and Arabic characters.
A thread on Reddit narrowed down the system crash and reboot errors to iOS Unicode handling. More specifically, the Unicode string in question is part of a much longer block of text that cannot be fully rendered in Notifications.
If a text or iMessage containing the text string is received by the device, and is displayed in the lock screen, or is shown as a drop-down notification, iOS eats up all of the available resources while attempting to render it. This eventually causes Springboard to crash. If the same message is received while in the conversation, problems don’t occur, indicating the issue may lie with how iOS renders notifications.
While some users have indicated they’ve had success turning off notifications for messages, others indicate that doesn’t fix the problem. If you’ve already experienced the issue, users have found that receiving a new message, sending out a photo from the Photos app, or sending yourself a message via Share sheets will stop the rogue process.