A use after free issue was addressed with improved memory management. This issue is fixed in macOS Monterey 12.3, iOS 15.4 and iPadOS 15.4, tvOS 15.4, Safari 15.4. Processing maliciously crafted web content may lead to arbitrary code execution.
https://support.apple.com/en-us/HT213187
https://support.apple.com/en-us/HT213186