The download function of Internet Explorer 6 SP1 allows remote attackers to obtain the cache directory name via an HTTP response with an invalid ContentType and a .htm file, which could allow remote attackers to bypass security mechanisms that rely on random names, as demonstrated by threadid10008.
https://exchange.xforce.ibmcloud.com/vulnerabilities/13847
http://www.safecenter.net/UMBRELLAWEBV4/threadid10008
http://marc.info/?l=bugtraq&m=107038202225587&w=2