An out-of-bounds read was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.0, tvOS 14.0, iOS 14.0 and iPadOS 14.0. An application may be able to execute arbitrary code with kernel privileges.
https://support.apple.com/en-us/HT211931
https://support.apple.com/en-us/HT211850
https://support.apple.com/en-us/HT211844