CVE-2006-6126 in Mac OS X Server
Summary
by MITRE
Apple Mac OS X allows local users to cause a denial of service (memory corruption) via a crafted Mach-O binary with a malformed load_command data structure.
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Analysis
by VulDB Data Team • 04/29/2026
The vulnerability described in CVE-2006-6126 represents a critical memory corruption issue within Apple Mac OS X operating systems that arises from improper handling of Mach-O binary format structures. This flaw specifically targets the load_command data structure within Mach-O executables, which serves as the fundamental mechanism for describing how executable files should be loaded into memory by the operating system's kernel. The vulnerability exists in the kernel-level Mach-O loader implementation that processes these binary files during execution, creating a pathway for malicious code to manipulate memory structures that should remain protected and properly validated.
The technical nature of this vulnerability stems from insufficient input validation within the kernel's Mach-O parsing routines. When a local attacker crafts a malicious Mach-O binary containing malformed load_command data structures, the kernel's loader fails to properly sanitize or validate these structures before processing them. This inadequate validation allows the malformed data to corrupt kernel memory spaces, potentially leading to system instability, unexpected crashes, or in some cases, arbitrary code execution. The vulnerability specifically affects the kernel's handling of the LC_LOAD_DYLIB, LC_LOAD_DYLINKER, and similar load commands that are integral to the dynamic linking process in mac os x systems. The flaw demonstrates characteristics consistent with a buffer over-read or improper memory access pattern that can be exploited through crafted input manipulation.
From an operational perspective, this vulnerability presents a significant risk to system stability and availability within mac os x environments. Local users who can execute arbitrary code on a target system can leverage this flaw to trigger denial of service conditions that may require system restarts or manual intervention to resolve. The impact extends beyond simple service disruption as memory corruption can potentially lead to more severe consequences including privilege escalation opportunities or system compromise. Attackers can exploit this vulnerability without requiring network access or elevated privileges, making it particularly dangerous in environments where local user access is common or where system administrators may not be immediately aware of the threat. The vulnerability affects multiple versions of mac os x and represents a fundamental flaw in the kernel's binary loading mechanism that impacts system reliability and security posture.
Mitigation strategies for this vulnerability should focus on immediate system updates and kernel patches provided by apple to address the specific memory corruption issue in the Mach-O loader. System administrators should implement comprehensive monitoring to detect unusual memory access patterns or kernel crashes that may indicate exploitation attempts. The implementation of additional security controls such as kernel extension validation and system integrity protection mechanisms can help reduce the attack surface. Organizations should also consider implementing user access controls to limit local execution privileges and ensure that only trusted users can execute binaries on critical systems. This vulnerability aligns with attack patterns documented in the attack tree framework where local privilege escalation and denial of service conditions are common exploitation vectors, and it represents a classic example of a memory safety issue that can be addressed through proper input validation and kernel memory protection mechanisms. The flaw demonstrates the importance of maintaining robust kernel-level validation routines and highlights the need for continuous security auditing of core operating system components that handle external input data structures.