CVE 2021-30951
A use after free issue was addressed with improved memory management. This issue is fixed in tvOS 15.2, macOS Monterey 12.1, Safari 15.2, iOS 15.2 and iPadOS 15.2, watchOS 8.3. Processing maliciously crafted web content may lead to arbitrary code execution.
See the 
CVE page on Mitre.org
for more details.
