Opera before 10.50 on Windows, before 10.52 on Mac OS X, and before 10.60 on UNIX platforms makes widget properties accessible to third-party domains, which allows remote attackers to obtain potentially sensitive information via a crafted web site.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11096
http://www.vupen.com/english/advisories/2010/1673
http://www.opera.com/support/search/view/959/
http://www.opera.com/docs/changelogs/windows/1050/