CVE 2018-4438
A logic issue existed resulting in memory corruption. This was addressed with improved state management. This issue affected versions prior to iOS 12.1.1, tvOS 12.1.1, watchOS 5.1.2, Safari 12.0.2, iTunes 12.9.2 for Windows, iCloud for Windows 7.9.
See the 
CVE page on Mitre.org
for more details.
