A logic issue was addressed with improved validation. This issue is fixed in iCloud for Windows 7.17, iTunes 12.10.4 for Windows, iCloud for Windows 10.9.2, tvOS 13.3.1, Safari 13.0.5, iOS 13.3.1 and iPadOS 13.3.1. A DOM object context may not have had a unique security origin.
https://support.apple.com/en-us/HT210948
https://support.apple.com/en-us/HT210947
https://support.apple.com/en-us/HT210923
https://support.apple.com/en-us/HT210922