CVE-2019-8528 in macOS
Summary
by MITRE • 10/28/2020
A use after free issue was addressed with improved memory management. This issue is fixed in watchOS 5.2, macOS Mojave 10.14.4, Security Update 2019-002 High Sierra, Security Update 2019-002 Sierra, iOS 12.2. An application may be able to execute arbitrary code with kernel privileges.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 04/24/2025
This vulnerability represents a critical use after free flaw that emerged in Apple's operating system ecosystems, specifically affecting multiple platforms including watchOS, macOS, and iOS. The issue stems from improper memory management practices where freed memory blocks are still accessible to applications, creating potential exploitation vectors for malicious code execution. The vulnerability was particularly concerning because it could be leveraged by an application to escalate privileges to kernel level access, fundamentally compromising system security. The root cause lies in the failure to properly invalidate memory references after deallocation, allowing for potential reuse of freed memory segments by unauthorized processes.
The technical exploitation of this vulnerability aligns with common attack patterns documented in the attack tactics and techniques framework, specifically relating to privilege escalation and code execution within kernel contexts. This type of flaw typically maps to CWE-416, which describes the use of freed memory condition, and can be categorized under the broader ATT&CK matrix domain of privilege escalation through kernel exploits. The vulnerability's impact extends across Apple's ecosystem due to shared kernel components and memory management subsystems, making it particularly dangerous as a single exploit could potentially affect multiple device types simultaneously. Attackers could craft malicious applications that trigger the use after free condition, leading to arbitrary code execution with the highest system privileges.
The operational implications of this vulnerability are severe, as it fundamentally undermines the security model of Apple's operating systems by allowing sandboxed applications to gain kernel-level access. This capability enables attackers to bypass all standard security boundaries, potentially leading to complete system compromise, data exfiltration, and persistent backdoor installation. The vulnerability's presence in multiple operating system versions means that organizations and individuals using affected devices face significant risk, as the exploit could be delivered through seemingly benign applications. The memory management flaw specifically affects how the kernel handles reference counting and memory deallocation processes, creating windows of opportunity for attackers to manipulate memory state during cleanup operations.
Apple's resolution of this vulnerability through security updates demonstrates the company's commitment to addressing kernel-level security issues promptly. The patches included in watchOS 5.2, macOS Mojave 10.14.4, and the respective security updates for High Sierra and Sierra implemented improved memory management controls and enhanced validation mechanisms for freed memory blocks. These mitigations likely involved strengthening reference counting mechanisms, implementing stricter memory access controls, and adding additional checks during memory deallocation processes. Organizations should prioritize deployment of these updates as they represent critical security fixes that address fundamental flaws in the operating system's core security architecture. The vulnerability's resolution also highlights the importance of continuous security monitoring and proactive patch management in preventing exploitation of kernel-level vulnerabilities that could lead to complete system compromise.