Launch Services in Apple Mac OS X 10.5.8 does not properly recognize an unsafe Uniform Type Identifier (UTI) in an exported document type in a downloaded application, which allows remote attackers to trigger the automatic opening of a file, and execute arbitrary code, via a crafted web site.
http://www.securityfocus.com/bid/36361
http://support.apple.com/kb/HT3865
http://secunia.com/advisories/36701
http://lists.apple.com/archives/security-announce/2009/Sep/msg00004.html