Multiple memory corruption issues were addressed with improved input validation. This issue is fixed in macOS Catalina 10.15, iOS 13, iCloud for Windows 7.14, iCloud for Windows 10.7, tvOS 13, macOS Catalina 10.15.1, Security Update 2019-001, and Security Update 2019-006, watchOS 6, iTunes 12.10.1 for Windows. Multiple issues in libxml2.
https://support.apple.com/en-us/HT210722
https://support.apple.com/en-us/HT210637
https://support.apple.com/en-us/HT210636
https://support.apple.com/en-us/HT210635
https://support.apple.com/en-us/HT210634
https://support.apple.com/en-us/HT210607