Opera 7.54 and earlier uses kfmclient exec to handle unknown MIME types, which allows remote attackers to execute arbitrary code via a shortcut or launcher that contains an Exec entry.

The Javascript engine in Opera 7.23 allows remote attackers to cause a denial of service (crash) by creating a new Array object with a large size value, then writing into that array.

Opera Browser 7.23, and other versions before 7.50, updates the address bar as soon as the user clicks a link, which allows remote attackers to redirect to other sites via the onUnload attribute.

A race condition in Opera web browser 7.53 Build 3850 causes Opera to fill in the address bar before the page has been loaded, which allows remote attackers to spoof the URL in the address bar via the window.open and location.replace HTML parameters, which facilitates phishing attacks.

Opera before 7.54 allows remote attackers to modify properties and methods of the location object and execute Javascript to read arbitrary files from the client's local filesystem or display a false URL to the user.

Opera allows remote attackers to cause a denial of service (invalid memory reference and application crash) via a web page or HTML email that contains a TBODY tag with a large COL SPAN value, as demonstrated by mangleme.

Opera 7.50 and earlier allows remote web sites to provide a "Shortcut Icon" (favicon) that is wider than expected, which could allow the web sites to spoof a trusted domain and facilitate phishing attacks using a wide icon and extra spaces.

Argument injection vulnerability in Opera before 7.50 does not properly filter "-" characters that begin a hostname in a telnet URI, which allows remote attackers to insert options to the resulting command line and overwrite arbitrary files via (1) the "-f" option on Windows XP or (2) the "-n" option on Linux.