A serious Apple iOS bug has been discovered that allows FaceTime users to access the microphone and front facing camera of who they are calling even if the person does not answer the call. The bug works in iOS 12.1.2 and we were able to hear and see the person. It is not known who first discovered this bug, but numerous people have been posting about it on social media and making video demonstrations. Apple has confirmed that they are “aware of this issue and we have identified a fix that will be released in a software update later this week”””
Source: https://www.bleepingcomputer.com/news/security/disable-facetime-now-bug-lets-callers-snoop-on-you-without-permission/