A logic issue was addressed with improved state management. This issue is fixed in macOS Monterey 12.0.1, iOS 15.1 and iPadOS 15.1, watchOS 8.1, tvOS 15.1. Processing maliciously crafted web content may lead to universal cross site scripting.
https://www.debian.org/security/2021/dsa-5031
https://www.debian.org/security/2021/dsa-5030
https://support.apple.com/en-us/HT212876
https://support.apple.com/en-us/HT212874
https://support.apple.com/en-us/HT212869