CVE-2019-8539

Vulnerability

A memory initialization issue exists in multiple versions of macOS, including macOS Mojave 10.14.5 and earlier. The bug is in the AppleGraphicsControl component and can be triggered by an application reading restricted memory due to insufficient input validation. Affected versions include macOS Mojave 10.14.5 and earlier, macOS High Sierra, and macOS Sierra. The issue is addressed in macOS Mojave 10.14.6, Security Update 2019-004 High Sierra, and Security Update 2019-004 Sierra [1].

Exploitation

An attacker needs to have the ability to run a malicious application on the target system. No additional privileges or user interaction beyond installing and executing the application is required. The application can exploit the memory initialization flaw to read restricted memory areas, potentially bypassing security barriers. The exact sequence of steps is not publicly detailed, but it involves triggering the vulnerability through the AppleGraphicsControl component [1].

Impact

If exploited, a malicious application may be able to read restricted memory and subsequently execute arbitrary code with system privileges. This could lead to full compromise of the affected macOS system, including unauthorized access to sensitive data, installation of malware, or persistent control [1].

Mitigation

The vulnerability is fixed in macOS Mojave 10.14.6, Security Update 2019-004 High Sierra, and Security Update 2019-004 Sierra, all released on July 22, 2019 [1]. Users should update to the latest available versions. No workarounds are mentioned in the advisory. Systems running unsupported versions (e.g., older macOS releases not covered) remain vulnerable.