According to people investigating the bug on reddit, the text causes iPhones running multiple versions of iOS to promptly crash. A flurry of Twitter users, angry that their devices fell victim to text messages, indicates that the bug is causing problems. Apple will almost certainly issue a fix. In the meantime, users can protect themselves against the nuisance text by going to system settings, navigating to Notifications>Messages>Show Previews, and turning it to off.
That change will prevent attacks that are currently circulating online, but it may not stop miscreants from finding new ways to crash people’s iDevices. According to the reddit thread, messages sent over WhatsApp may also trigger the crash. And depending on the way individual apps parse Unicode glyphs, other programs may do the same thing. The bug can also trip up OS X, although the attack requires a target to concatenate or paste a malicious file into the Mac terminal, according to a researcher who goes by the Twitter handle Hacker Fantastic.