An out-of-bounds write issue was addressed with improved bounds checking. 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. An application may be able to execute arbitrary code with kernel privileges.
https://www.zerodayinitiative.com/advisories/ZDI-21-486/