A design error in Opera 8.01 and earlier allows user-assisted attackers to execute arbitrary code by overlaying a malicious new window above a file download dialog box, then tricking the user into double-clicking on the "Run" button, aka "link hijacking".
Improper Restriction of Rendered UI Layers or Frames The web application does not restrict or incorrectly restricts frame objects or UI layers that belong to another application or domain.