Opera before 10.60 on Windows and Mac OS X does not properly prevent certain double-click operations from running a program located on a web site, which allows user-assisted remote attackers to execute arbitrary code via a crafted web page that bypasses a dialog.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11856
http://www.vupen.com/english/advisories/2010/1664
http://www.opera.com/support/search/view/957/
http://www.opera.com/docs/changelogs/windows/1060/