An information disclosure vulnerability exists in the Windows Event Viewer (eventvwr.msc) when it improperly parses XML input containing a reference to an external entity. An attacker who successfully exploited this vulnerability could read arbitrary files via an XML external entity (XXE) declaration. To exploit the vulnerability, an attacker could create a file containing specially crafted XML content and convince an authenticated user to import the file. The update addresses the vulnerability by modifying the way that the Event Viewer parses XML input.