Multiple unspecified vulnerabilities in Opera 8.50 on Linux and Windows have unknown impact and attack vectors, related to (1) " handling of must-revalidate cache directive for HTTPS pages" or (2) a "display issue with cookie comment encoding."
The mail client in Opera before 8.50 opens attached files from the user's cache directory without warning the user, which might allow remote attackers to inject arbitrary web script and spoof attachment filenames.
Opera before 8.50 allows remote attackers to spoof the content type of files via a filename with a trailing "." (dot), which might allow remote attackers to trick users into processing dangerous content.
Opera 8.01, when the "Arial Unicode MS" font (ARIALUNI.TTF) is installed, does not properly handle extended ASCII characters in the file download dialog box, which allows remote attackers to spoof file extensions and possibly trick users into executing arbitrary code.
Opera 8.01 allows remote attackers to conduct cross-site scripting (XSS) attacks or modify which files are uploaded by tricking a user into dragging an image that is a "javascript:" URI.
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".
Opera 7.x and 8 before 8.01 does not clearly associate a Javascript dialog box with the web page that generated it, which allows remote attackers to spoof a dialog box from a trusted site and facilitates phishing attacks, aka the "Dialog Origin Spoofing Vulnerability."
The XMLHttpRequest object in Opera 8.0 Final Build 1095 allows remote attackers to bypass access restrictions and perform unauthorized actions on other domains via a redirect.