A memory corruption issue was addressed with improved input validation. This issue is fixed in iOS 12.1.3, macOS Mojave 10.14.3, tvOS 12.1.2. A malicious application may be able to execute arbitrary code with kernel privileges.
https://www.exploit-db.com/exploits/46297/
https://support.apple.com/HT209447
https://support.apple.com/HT209446