If you use an iPhone you should update the operating system to version 9.3.3 immediately.
Researchers have confirmed an exploit can be created to use a multimedia message (MMS) inside a Tagged Image File Format (TIFF). The phone owner doesn't have to do anything for the exploit to run.
From there the exploit could leak credentials stored in memory to the attacker.
You can read more about the issue in a Forbes article HERE.
Update and tell your friends.