Certain types of HTTP responses and redirections can cause Opera to mistakenly give elevated privileges to remote web pages. These pages can then use their elevated privileges to load files from the user's computer as web page resources. This may allow scraping of potentially sensitive information from those files.
Opera Software has released Opera 11.01, where these issues have been fixed.
Need help? Hit F1 anytime while using Opera to access our online help files, or go here.