A use after free issue was addressed with improved memory management. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.0, iOS 14.0 and iPadOS 14.0, macOS Catalina 10.15.6, Security Update 2020-004 Mojave, Security Update 2020-004 High Sierra, tvOS 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
https://support.apple.com/en-us/HT211843