Buffer overflow in the HTML Help ActiveX Control (hhctrl.ocx) in Microsoft Windows 98, 98 Second Edition, Millennium Edition, NT 4.0, NT 4.0 Terminal Server Edition, Windows 2000, and Windows XP allows remote attackers to execute code via (1) a long parameter to the Alink function, or (2) script containing a long argument to the showHelp function.

The HTML Help facility in Microsoft Windows 98, 98 Second Edition, Millennium Edition, NT 4.0, NT 4.0 Terminal Server Edition, Windows 2000, and Windows XP uses the Local Computer Security Zone when opening .chm files from the Temporary Internet Files folder, which allows remote attackers to execute arbitrary code via HTML mail that references or inserts a malicious .chm file containing shortcuts that can be executed, aka "Code Execution via Compiled HTML Help File."

A handler routine for the Network Connection Manager (NCM) in Windows 2000 allows local users to gain privileges via a complex attack that causes the handler to run in the LocalSystem context with user-specified code.

Microsoft Windows 2000 running the Terminal Server 90-day trial version, and possibly other versions, does not apply group policies to incoming users when the number of connections to the SYSVOL share exceeds the maximum, e.g. with a maximum number of licenses, which can allow remote authenticated users to bypass group policies.