Multiple memory corruption issues were addressed with improved memory handling. This issue is fixed in iOS 12.1.3, tvOS 12.1.2, Safari 12.0.3, iTunes 12.9.3 for Windows, iCloud for Windows 7.10. Processing maliciously crafted web content may lead to arbitrary code execution.
https://usn.ubuntu.com/3889-1/
https://support.apple.com/HT209451
https://support.apple.com/HT209450
https://support.apple.com/HT209449
https://support.apple.com/HT209447
https://support.apple.com/HT209443