An out-of-bounds read was addressed with improved input validation. This issue is fixed in iOS 14.2 and iPadOS 14.2, tvOS 14.2, watchOS 7.1. Processing a maliciously crafted audio file may lead to arbitrary code execution.
https://www.zerodayinitiative.com/advisories/ZDI-21-374/
https://support.apple.com/kb/HT211931
https://support.apple.com/en-us/HT211930
https://support.apple.com/en-us/HT211929