Another one? Come on Microsoft, Smart people use Firefox www.mozilla.org. There is a window() object that fails to check code passed thru it correctly. An attacker can execute code to launch a shell and take over the computer. The IE user would have to view a HTML documnent or email to be affected.
Disable Active scripting.
Follow this link to check out a paper on malicious active scritping:
http://www.cert.org/tech_tips/malicious_code_FAQ.html#ie56