A use after free issue was addressed with improved memory management. This issue is fixed in Safari 15, tvOS 15, watchOS 8, iOS 15 and iPadOS 15. Processing maliciously crafted web content may lead to arbitrary code execution.
The MITRE CVE dictionary describes this issue as:
A use after free issue was addressed with improved memory management. This issue is fixed in Safari 15, tvOS 15, watchOS 8, iOS 15 and iPadOS 15. Processing maliciously crafted web content may lead to arbitrary code execution.