When a user clicks a link on a Web page that points to an executable file, Opera will show a download dialog to allow the user to download it. The dialog will allow the user to choose to run the executable directly. If the user accidentally double clicks, the second click will activate whatever is now under the mouse. A carefully constructed page could cause the second click to activate the buttons on the dialog, allowing the executable to run.
Previous versions of Opera had a delay before the button would respond to counteract this possibility. A recent interface change caused this protection not to function correctly.
This issue affects Opera for Windows and Mac.
Opera Software has released Opera 10.60 where this issue has been fixed.