Quote:macOS Big Sur 11.6​
Released: September 13, 2021

CoreGraphics
Available for: macOS Big Sur
Impact: Processing a maliciously crafted PDF may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited.
Description: An integer overflow was addressed with improved input validation.
CVE-2021-30860: The Citizen Lab

WebKit
Available for: macOS Big Sur
Impact: Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited.
Description: A use after free issue was addressed with improved memory management.
CVE-2021-30858: an anonymous researcher