A logic issue was addressed with improved validation. This issue is fixed in macOS Big Sur 11.4, tvOS 14.6, watchOS 7.5, iOS 14.6 and iPadOS 14.6. A malicious application may be able to execute arbitrary code with kernel privileges.
https://support.apple.com/en-us/HT212533
https://support.apple.com/en-us/HT212532