The screen saver in Windows NT does not verify that its security context has been changed properly, allowing attackers to run programs with elevated privileges.
Windows 95, 98, and NT 4.0 allow remote attackers to cause a denial of service by spoofing ICMP redirect messages from a router, which causes Windows to change its routing tables.
The cryptographic challenge of SMB authentication in Windows 95 and Windows 98 can be reused, allowing an attacker to replay the response and impersonate a user.
The Forms 2.0 ActiveX control (included with Visual Basic for Applications 5.0) can be used to read text from a user's clipboard when the user accesses documents with ActiveX content.