Cisco has found a vulnerability similar to the Android text exploit, which could take control of your mobile phone through a text message. Leo says that Apple has released a patch to close the hole before anyone else had discovered it. This affects iOS, watchOS, macOS, and tvOS. Mavericks and Yosemite users don't have a fix yet, though, so those users should disable iMessage until they do. If you can't get past Mavericks because your desktop is too old, turn off iMessages permanently.