A use after free issue was addressed with improved memory management. This issue is fixed in iOS 15.5 and iPadOS 15.5, macOS Monterey 12.4, tvOS 15.5, watchOS 8.6. Processing maliciously crafted web content may lead to arbitrary code execution.
https://support.apple.com/en-us/HT213258
https://support.apple.com/en-us/HT213257