CVE-2021-30793

Vulnerability

A logic issue existed in the macOS kernel, leading to a memory corruption condition. The vulnerability is present in macOS Big Sur, Catalina, and Mojave. Apple addressed the issue in macOS Big Sur 11.5, Security Update 2021-004 Catalina, and Security Update 2021-005 Mojave [1][2][3]. The official description notes a memory corruption issue resolved with improved input validation [1][2][3].

Exploitation

An attacker would need to have the ability to run a malicious application on the affected system. The vulnerability does not require any special system privileges beyond application execution. The exact exploitation steps are not disclosed in the available references; however, the issue is classified as a logic issue that can be triggered by an untrusted application to corrupt kernel memory.

Impact

Successful exploitation allows an application to execute arbitrary code with kernel privileges, leading to full compromise of the operating system. The attacker gains the highest possible privilege level (kernel), potentially allowing them to bypass security mechanisms, access sensitive data, and install persistent malware.

Mitigation

The vulnerability is fixed in macOS Big Sur 11.5, Security Update 2021-004 Catalina, and Security Update 2021-005 Mojave, all released on July 21, 2021 [1][2][3]. Users should update their macOS to the latest available version. No workarounds are provided. No known exploitation in the wild has been reported in the references.