The downloads manager in Opera before 11.01 on Windows does not properly determine the pathname of the filesystem-viewing application, which allows user-assisted remote attackers to execute arbitrary code via a crafted web site that hosts an executable file.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12369
http://www.vupen.com/english/advisories/2011/0231
http://www.opera.com/support/kb/view/985/
http://www.opera.com/docs/changelogs/windows/1101/
http://secunia.com/advisories/43023