An issue was discovered in certain Apple products. iOS before 10.2 is affected. macOS before 10.12.2 is affected. watchOS before 3.1.3 is affected. The issue involves the "CoreMedia Playback" component. It allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted MP4 file.
https://support.apple.com/HT207487
https://support.apple.com/HT207423
https://support.apple.com/HT207422