Add or Remove Programs entry for Windows XP Hotfix - KB890175. This hotfix addresses a vulnerability in HTML Help that could allow code execution.
A cross-domain vulnerability exists in HTML Help ActiveX control that could allow information disclosure or remote code execution on an affected system. An attacker could exploit the vulnerability by constructing a malicious Web page that could potentially allow remote code execution if a user visited that page. An attacker who successfully exploited this vulnerability could take complete control of an affected system.