Internet Explorer 4 allows remote attackers (malicious web site operators) to read the contents of the clipboard via the Internet WebBrowser ActiveX object.
Internet Explorer 4.01 allows remote attackers to read arbitrary files by pasting a file name into the file upload control, aka untrusted scripted paste.
Internet Explorer 4.0 allows remote attackers to cause a denial of service (crash) via HTML code that contains a long CLASSID parameter in an OBJECT tag.
A configuration in a web browser such as Internet Explorer or Netscape Navigator allows execution of active content such as ActiveX, Java, Javascript, etc.
Internet Explorer 3 records a history of all URL's that are visited by a user in DAT files located in the Temporary Internet Files and History folders, which are not cleared when the user selects the "Clear History" option, and are not visible when the user browses the folders because of tailored displays.
JavaScript in Internet Explorer 3.x and 4.x, and Netscape 2.x, 3.x and 4.x, allows remote attackers to monitor a user's web activities, aka the Bell Labs vulnerability.