This issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.4, tvOS 14.6, watchOS 7.5, iOS 14.6 and iPadOS 14.6. Processing a maliciously crafted audio file may lead to arbitrary code execution.
https://support.apple.com/en-us/HT212533
https://support.apple.com/en-us/HT212532