Apple told MacRumors that a fix for the “chaiOS” bug is coming in a software update (or two) next week. Look for the solutions to come in iOS 11.2.5 and perhaps macOS High Sierra 10.13.3.
The bug appeared on Jan. 17 after it was shared on Twitter. When texted to an iOS device, it is able to cause the Messages app on the iPhone or iPad to freeze up and become unusable. The Safari and Chrome browsers on Macs are also affected.
