Secunia Research has discovered a vulnerability in Opera, which can be exploited by malicious web sites to spoof dialog boxes.

Inactive tabs can launch dialog boxes so they appear to be displayed by a web site in another tab. This can be exploited by a malicious web site to show a dialog box, which seems to originate from a trusted web site.

Successful exploitation would normally require that a user is tricked into opening a link from a malicious web site to a trusted web site in a new tab.

A test is available here:
http://secunia.com/multiple_browsers_dialog_box_spoofing_test/

The vulnerability has been confirmed in Opera 7.54. Other versions may also be vulnerable.

Solution
The vulnerability has been addressed in the 8.0 beta2 preview release.

Provided and/or discovered by
Jakob Balle, Secunia Research.

Changelog
Further details available to Secunia VIM customers

Original Advisory
Opera Software:
http://www.opera.com/support/search/supsearch.dml?index=781

Secunia:
http://secunia.com/secunia_research/2004-10/

Deep Links
Links available to Secunia VIM customers