If you haven't updated already, it's probably best you do it ASAP!
Apple has advised that “viewing a maliciously crafted JPEG file may lead to arbitrary code execution”. That means that hackers could simply design an image file to break into the phone, send it to their victim, and get control of their phone if the apparently innocent picture was opened.
The file doesn’t have to be downloaded or installed to work, but rather just get opened. That means that it could hit people from anywhere on the web, or just while receiving a message from someone who appears to be a friend.
Apple says that any iPhone 5 or later, a fourth generation iPad or later and 6th generation or later iPod Touches can be hit by the bug. The company hasn’t said which iOS versions were impacted so it is safest to assume that any up until the new update could be vulnerable.
The company also hasn’t said how the bug would work in practice. That measure helps keep the hack more private – but, given that hackers will likely work it out soon, it also means that it’s harder to stay safe from it without downloading the update.