An out-of-bounds write issue was addressed with improved input validation. This issue is fixed in iOS 15.6 and iPadOS 15.6, watchOS 8.7, tvOS 15.6, macOS Monterey 12.5, Safari 15.6. Processing maliciously crafted web content may lead to arbitrary code execution.
https://support.apple.com/en-us/HT213346
https://support.apple.com/en-us/HT213345
https://support.apple.com/en-us/HT213342