An out-of-bounds read was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.0.1, 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.
http://seclists.org/fulldisclosure/2020/Dec/26
http://seclists.org/fulldisclosure/2020/Dec/32
https://support.apple.com/en-us/HT211928
https://support.apple.com/en-us/HT211929
https://support.apple.com/en-us/HT211930