CVE-2021-30805: 
macOS vulnerability analysis and mitigation

CVE-2021-30805 is a memory corruption vulnerability discovered in the AMD Kernel component of macOS operating systems. The vulnerability was disclosed and patched by Apple on July 21, 2021, affecting multiple versions including macOS Big Sur, Catalina, and Mojave. The issue was identified by ABC Research s.r.o and allows an application to potentially execute arbitrary code with kernel privileges (Apple Support, NVD).

The vulnerability is characterized as a memory corruption issue in the AMD Kernel component that was addressed with improved input validation. It received a CVSS v3.1 Base Score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, and a CVSS v2.0 Base Score of 10.0 (HIGH) with vector (AV:N/AC:L/Au:N/C:C/I:C/A:C). The vulnerability is classified under CWE-787 (Out-of-bounds Write) (NVD).

The vulnerability allows an application to execute arbitrary code with kernel privileges, which represents the highest level of system access. This could potentially lead to complete system compromise, allowing an attacker to take full control of the affected system (Apple Support, NVD).

Apple addressed this vulnerability by implementing improved input validation in the following security updates: macOS Big Sur 11.5, Security Update 2021-004 Catalina, and Security Update 2021-005 Mojave. Users are advised to update their systems to these versions or later to mitigate the risk (Apple Support).