CVE-2019-8696 in macOS
Summary
by MITRE • 10/28/2020
A buffer overflow issue was addressed with improved memory handling. This issue is fixed in macOS Mojave 10.14.6, Security Update 2019-004 High Sierra, Security Update 2019-004 Sierra. An attacker in a privileged network position may be able to execute arbitrary code.
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Analysis
by VulDB Data Team • 10/17/2025
The vulnerability identified as CVE-2019-8696 represents a critical buffer overflow condition that existed within Apple's operating system implementations. This flaw emerged from inadequate memory management practices during the processing of certain network protocols or system calls, creating a pathway for malicious actors to exploit the system's memory handling mechanisms. The issue was particularly concerning because it could be leveraged by attackers who had already gained a privileged network position, meaning they were able to monitor or manipulate network traffic between systems. The vulnerability's classification aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. Such buffer overflows are among the most common and dangerous classes of vulnerabilities in system software, as they can lead to complete system compromise through arbitrary code execution.
The technical implementation of this vulnerability stemmed from insufficient validation of input data within the network processing components of macOS and related operating systems. When legitimate network traffic was processed through affected system components, the software failed to properly validate the size and content of incoming data buffers, allowing an attacker to craft malicious payloads that would overflow the allocated memory space. This overflow could overwrite critical system memory regions including return addresses, function pointers, or other control data structures essential for proper program execution. The exploitability of this vulnerability was significantly enhanced by the fact that it required only a privileged network position, meaning attackers who could intercept or manipulate network traffic between communicating systems could potentially leverage this flaw without requiring additional authentication or local access to the target machine.
The operational impact of CVE-2019-8696 extended beyond simple code execution capabilities to encompass potential system compromise and data breach scenarios. Attackers who successfully exploited this vulnerability could execute arbitrary code with the privileges of the affected system process, potentially leading to full system control, data exfiltration, or establishment of persistent backdoors. The vulnerability's presence in multiple versions of Apple's operating systems including macOS Mojave 10.14.6, Security Update 2019-004 High Sierra, and Security Update 2019-004 Sierra meant that organizations running these versions were all at risk. The attack surface was particularly broad since network-based exploitation required minimal prerequisites beyond network access, making it a significant concern for enterprise environments where network monitoring and traffic interception might be possible. This vulnerability's characteristics align with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, demonstrating how such buffer overflows can serve as initial access vectors for broader attack campaigns.
The remediation of CVE-2019-8696 required comprehensive memory handling improvements implemented through Apple's security updates. The patches released for macOS Mojave 10.14.6, Security Update 2019-004 High Sierra, and Security Update 2019-004 Sierra addressed the underlying buffer overflow conditions through enhanced bounds checking, improved memory allocation routines, and stricter input validation mechanisms. These updates implemented proper memory management practices that prevent the overflow conditions from occurring by ensuring that all input data is properly validated before being processed into system memory buffers. Organizations were strongly advised to implement these security updates immediately, as the vulnerability could be exploited remotely with minimal effort once an attacker gained network access to the target system. The fix demonstrated Apple's commitment to addressing memory safety issues in their operating system components and highlighted the importance of regular security updates in maintaining system integrity against known vulnerabilities. The resolution of this vulnerability through improved memory handling practices represents a standard approach to mitigating buffer overflow threats, aligning with industry best practices for secure coding and defensive programming techniques that should be implemented across all system software components.