CVE-2010-0056 in Mac OS X
Summary
by MITRE
Buffer overflow in Cocoa spell checking in AppKit in Apple Mac OS X 10.5.8 allows user-assisted remote attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted document.
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Analysis
by VulDB Data Team • 05/03/2026
The vulnerability identified as CVE-2010-0056 represents a critical buffer overflow flaw within the Cocoa spell checking functionality of AppKit in Apple Mac OS X 10.5.8 operating system. This issue resides in the core text processing components that handle spell checking operations, making it particularly dangerous as it can be triggered through seemingly benign document interactions. The buffer overflow occurs when the spell checking system processes malformed or specially crafted text inputs that exceed the allocated memory buffers, creating potential entry points for malicious code execution.
The technical nature of this vulnerability stems from inadequate input validation and memory management within the spell checking subsystem. When a document containing maliciously crafted text is processed by the spell checking engine, the system fails to properly bounds-check the data before copying it into fixed-size memory buffers. This fundamental flaw allows attackers to overwrite adjacent memory locations, potentially corrupting critical program structures or injecting executable code. The vulnerability operates under CWE-121, which classifies buffer overflow conditions where insufficient bounds checking allows memory to be overwritten, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter. The attack vector is classified as user-assisted remote, meaning that a malicious document must be opened or processed by the victim, but the attacker does not need to be physically present or have direct system access.
The operational impact of this vulnerability extends beyond simple application crashes, presenting significant security risks to Mac OS X users. Successful exploitation could result in arbitrary code execution with the privileges of the affected application, potentially leading to full system compromise. The vulnerability affects the core operating system components, making it particularly dangerous as it could be leveraged to bypass security controls or establish persistent access. Applications utilizing the spell checking functionality, including text editors, word processors, and email clients, would be susceptible to this attack. The denial of service aspect of the vulnerability could also be exploited to disrupt normal system operations, creating availability issues for users and potentially impacting business continuity. This vulnerability demonstrates the critical importance of proper memory management in system-level components and highlights the risks associated with complex text processing systems.
Mitigation strategies for CVE-2010-0056 should focus on immediate patching and system hardening measures. Apple released security updates addressing this vulnerability, and users should ensure their systems are updated to the latest versions of Mac OS X 10.5.8 or later. Organizations should implement network monitoring to detect potential exploitation attempts and consider restricting document processing from untrusted sources. The vulnerability underscores the need for robust input validation and memory safety practices in software development, particularly for system-level components that handle user input. Security teams should conduct regular vulnerability assessments focusing on text processing components and ensure that all system components are kept up to date with security patches. Additionally, user education regarding the risks of opening documents from unknown sources remains crucial in preventing exploitation of this class of vulnerability, as the user-assisted nature of the attack requires user interaction to be successful.