CVE-2003-0010 in Windows
Summary
by MITRE
Integer overflow in JsArrayFunctionHeapSort function used by Windows Script Engine for JScript (JScript.dll) on various Windows operating system allows remote attackers to execute arbitrary code via a malicious web page or HTML e-mail that uses a large array index value that enables a heap-based buffer overflow attack.
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Analysis
by VulDB Data Team • 08/26/2025
The vulnerability identified as CVE-2003-0010 represents a critical integer overflow flaw within the JavaScript scripting engine of Microsoft Windows operating systems. This vulnerability specifically affects the JsArrayFunctionHeapSort function within JScript.dll, which is the core component responsible for handling array sorting operations in the Windows Scripting environment. The flaw manifests when processing large array index values during heap-based sorting operations, creating conditions that can be exploited to manipulate memory allocation and execution flow. This issue impacts multiple versions of Windows including Windows 2000, Windows XP, and Windows Server 2003, making it a widespread concern across enterprise and desktop environments that relied heavily on script-based web content and email processing.
The technical nature of this vulnerability stems from improper bounds checking within the heap sorting algorithm implementation. When a malicious web page or HTML email contains an array with an exceptionally large index value, the JsArrayFunctionHeapSort function fails to properly validate the integer parameters before performing memory allocation operations. This integer overflow condition causes the system to allocate insufficient memory for the buffer, leading to a heap-based buffer overflow scenario. The overflow occurs because the system calculates memory requirements using an integer value that exceeds the maximum representable value, resulting in a negative or excessively large memory allocation that corrupts adjacent heap memory regions. This memory corruption can be leveraged to overwrite critical execution pointers, function return addresses, or other program state information, effectively allowing remote attackers to redirect program execution flow.
The operational impact of this vulnerability extends beyond simple code execution, as it represents a sophisticated attack vector that can be weaponized through web-based delivery mechanisms. Attackers can craft malicious HTML content that, when processed by vulnerable Windows systems, triggers the exploitable condition through standard web browsing or email client operations. The vulnerability is particularly dangerous because it operates at the scripting engine level, meaning that any application relying on Windows Scripting Host or Internet Explorer's script execution capabilities becomes a potential target. This makes the attack surface extremely broad, affecting not only web browsers but also email clients, web applications, and any system component that processes JavaScript or VBScript content. The vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions that can lead to buffer overflows and memory corruption attacks.
Mitigation strategies for this vulnerability require immediate patch deployment through Microsoft's security updates, as the primary fix involves correcting the integer overflow handling within the JScript.dll component. Organizations should prioritize patch management processes to ensure all affected Windows systems receive the appropriate security updates. Additional defensive measures include implementing content filtering mechanisms to block potentially malicious HTML content, configuring web browsers with enhanced security settings, and deploying intrusion detection systems that can identify exploitation attempts. The vulnerability demonstrates the importance of proper input validation and memory management in scripting engines, and aligns with ATT&CK technique T1059.007 for Windows Scripting Host and T1203 for exploitation through web-based delivery methods. Network segmentation and application whitelisting can provide additional layers of protection while patches are being deployed, though these measures do not address the underlying vulnerability itself and should be considered temporary mitigations rather than permanent solutions.