A validation issue existed in the handling of symlinks. This issue was addressed with improved validation of symlinks. This issue is fixed in Security Update 2021-005 Catalina, iOS 14.8 and iPadOS 14.8, iOS 15 and iPadOS 15, watchOS 8, macOS Big Sur 11.6. An application may be able to access restricted files.
https://support.apple.com/kb/HT212815
https://support.apple.com/en-us/HT212819
https://support.apple.com/en-us/HT212814
https://support.apple.com/en-us/HT212807