For the sake of intrigue and humor, I'm just going to go ahead and publish thus sensationalized headline for normal media outlets to feed off of. Jamie Condliffe at Gizmodo writes:
" A newly discovered bug seems to cause Messages on iOS to crash when a specific string of text is received—and if it happens while the phone is locked, it also seems to reboot the iPhone too."
Yes, this string of characters exists and is annoying for a moment, but I'm quite sure a group of highly qualified engineers on call in Cupertino has already fixed such an issue and twenty other related bugs we don't know about. A new patch for iOS will be published next week and all will be swell. Heck, Tim Cook will probably make a joke about it at WWDC. Mute the annoying people that send it to you and move along, nothing to see here.