About Apple security updates
For our customers' protection, Apple doesn't disclose, discuss, or confirm security issues until an investigation has occurred and patches or releases are available. Recent releases are listed on the Apple security updates page.
Apple security documents reference vulnerabilities by CVE-ID when possible.
For more information about security, see the Apple Product Security page.
Released April 26, 2021
Available for: macOS Big Sur 11 and later
Impact: A remote attacker may be able to cause arbitrary code execution
Description: This issue was addressed with improved checks.
CVE-2021-21300: an anonymous researcher