Apple Safari before 3.1.2 on Windows does not properly interpret the URLACTION_SHELL_EXECUTE_HIGHRISK Internet Explorer zone setting, which allows remote attackers to bypass intended access restrictions, and force a client system to download and execute arbitrary files.
http://www.vupen.com/english/advisories/2008/1882/references
http://www.securitytracker.com/id?1020329
http://www.securityfocus.com/bid/29835
http://www.kb.cert.org/vuls/id/127185
http://secunia.com/advisories/30775
http://lists.apple.com/archives/security-announce/2008//Jun/msg00001.html