http://secunia.com/advisories/22477

A vulnerability has been discovered in Internet Explorer, which can be exploited by malicious people to disclose potentially sensitive information.
The vulnerability is caused due to an error in the handling of redirections for URLs with the "mhtml:" URI handler. This can be exploited to access documents served from another web site.
Secunia has constructed a test, which is available at:
http://secunia.com/Internet_Explorer_Arbitrary_Content_Disclosure_Vul nerability_Test/