CVE-2000-0464 in Internet Explorer
Summary
by MITRE
Internet Explorer 4.x and 5.x allows remote attackers to execute arbitrary commands via a buffer overflow in the ActiveX parameter parsing capability, aka the "Malformed Component Attribute" vulnerability.
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Analysis
by VulDB Data Team • 04/21/2026
The CVE-2000-0464 vulnerability represents a critical buffer overflow flaw in Microsoft Internet Explorer versions 4.x and 5.x that specifically targets the ActiveX component parameter parsing functionality. This vulnerability operates at the core of web browser security by exploiting how Internet Explorer handles ActiveX controls when processing web content, creating a pathway for remote code execution attacks. The flaw occurs when the browser encounters malformed component attributes in web pages, particularly those containing overly long or improperly formatted parameter strings that exceed the allocated buffer space within the ActiveX parsing mechanism.
The technical implementation of this vulnerability stems from insufficient input validation within the ActiveX control handling subsystem of Internet Explorer. When a malicious web page loads with specially crafted ActiveX parameters, the browser's parsing routine fails to properly bounds-check the incoming data before copying it into fixed-size memory buffers. This classic buffer overflow condition allows attackers to overwrite adjacent memory locations, potentially including return addresses and executable code segments, thereby enabling arbitrary code execution with the privileges of the user running the affected browser. The vulnerability is particularly dangerous because it can be triggered through normal web browsing activities without requiring any special user interaction beyond visiting a malicious website.
The operational impact of CVE-2000-0464 extends far beyond simple remote code execution, as it represents a fundamental compromise of user system integrity and network security. Attackers can leverage this vulnerability to install malware, steal sensitive information, modify system configurations, or establish persistent backdoors on compromised systems. The widespread adoption of Internet Explorer 4.x and 5.x during the late 1990s meant that this vulnerability affected millions of users across corporate and personal networks, creating significant risk for organizations relying on these browsers for web-based operations. The vulnerability also demonstrates the inherent risks of ActiveX technology, which was designed to enable rich web applications but became a primary attack vector for numerous security exploits during this era.
Security professionals should recognize this vulnerability as a classic example of insufficient input validation and memory safety issues that fall under CWE-121, which addresses buffer overflow conditions in heap-based memory management. The attack pattern aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation typically involves executing malicious code within the browser's execution context. Mitigation strategies should include immediate patch deployment through Microsoft's security updates, browser isolation techniques, and network-based protections such as web application firewalls that can detect and block malicious ActiveX parameter sequences. Organizations should also consider implementing browser security policies that restrict ActiveX control usage, disable unnecessary ActiveX components, and maintain comprehensive monitoring for suspicious network traffic patterns that may indicate exploitation attempts. The vulnerability serves as a historical reminder of the importance of secure coding practices and the need for robust input validation in web browser implementations.