CVE-2020-29612 in macOS
Summary
by MITRE • 04/03/2021
An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in macOS Big Sur 11.1, Security Update 2020-001 Catalina, Security Update 2020-007 Mojave. A malicious application may be able to execute arbitrary code with system privileges.
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Analysis
by VulDB Data Team • 05/24/2026
This vulnerability represents a critical out-of-bounds write flaw that emerged in Apple's macOS operating system across multiple versions including Big Sur 11.1, Catalina with Security Update 2020-001, and Mojave with Security Update 2020-007. The issue stems from insufficient bounds checking mechanisms within the system's memory management operations, creating a pathway for malicious code execution. From a cybersecurity perspective, this vulnerability aligns with CWE-787 Out-of-bounds Write, which specifically addresses memory corruption issues that occur when a program writes data beyond the boundaries of a fixed-length buffer. The flaw operates at the kernel level where applications can manipulate memory structures without proper validation, potentially allowing an attacker to overwrite critical system data structures or executable code segments.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables a malicious application to execute arbitrary code with system privileges, effectively granting the attacker complete control over the affected system. This represents a severe escalation from user-level to system-level privileges, which is particularly concerning given that the vulnerability can be exploited through a malicious application rather than requiring physical access or specialized attack vectors. The exploitation mechanism typically involves crafting specific inputs or memory operations that trigger the out-of-bounds write condition, potentially leading to code execution within the kernel context where all system protections are bypassed.
From an ATT&CK framework perspective, this vulnerability maps directly to several techniques including T1068 Exploitation for Privilege Escalation and T1547.001 Registry Run Keys / Startup Folder, as the malicious application could potentially establish persistence mechanisms through system-level modifications. The vulnerability also relates to T1059 Command and Scripting Interpreter where an attacker could execute arbitrary commands through the compromised system privileges. Security researchers have noted that such out-of-bounds write vulnerabilities often serve as initial access points for more sophisticated attack chains, as they provide the foundation for privilege escalation and system compromise that can then be leveraged for data exfiltration, lateral movement, or establishment of persistent backdoors.
The remediation strategy focuses on implementing robust bounds checking mechanisms that validate all memory access operations before allowing data to be written to allocated memory regions. Apple's security updates address this by strengthening memory management routines and incorporating additional validation checks that prevent malicious applications from triggering the out-of-bounds write condition. Organizations should prioritize immediate deployment of the applicable security updates, particularly in environments where untrusted applications may be executed or where the system is exposed to potential malicious actors. The vulnerability also underscores the importance of application sandboxing and privilege separation mechanisms, as these controls can limit the potential impact even if such memory corruption vulnerabilities are exploited. Regular security assessments and monitoring for unusual system behavior should be implemented to detect potential exploitation attempts, while maintaining comprehensive system logs to aid in forensic analysis should an incident occur.