Opera before 10.00 does not properly display all characters in Internationalized Domain Names (IDN) in the address bar, which allows remote attackers to spoof URLs and conduct phishing attacks, related to Unicode and Punycode.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6235
http://www.opera.com/support/kb/view/932/
http://www.opera.com/docs/changelogs/windows/1000/
http://www.opera.com/docs/changelogs/solaris/1000/
http://www.opera.com/docs/changelogs/mac/1000/