Opera before 10.54 on Windows and Mac OS X does not properly enforce permission requirements for widget filesystem access and directory selection, which allows user-assisted remote attackers to create or modify arbitrary files, and consequently execute arbitrary code, via widget File I/O operations.
secunia.com/advisories/40250
www.opera.com/docs/changelogs/mac/1054/
www.opera.com/docs/changelogs/windows/1054/
www.opera.com/support/kb/view/962/
www.securityfocus.com/bid/40973
www.vupen.com/english/advisories/2010/1529
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11950