A logic issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.1, Security Update 2020-001 Catalina, Security Update 2020-007 Mojave, macOS Big Sur 11.0.1, iOS 14.2 and iPadOS 14.2, watchOS 7.1, tvOS 14.2. Processing a maliciously crafted font file may lead to arbitrary code execution.
https://support.apple.com/en-us/HT212011
https://support.apple.com/en-us/HT211931
https://support.apple.com/en-us/HT211930