The International Domain Name (IDN) support in Firefox 1.0, Camino .8.5, and Mozilla before 1.7.6 allows remote attackers to spoof domain names using punycode encoded domain names that are decoded in URLs and SSL certificates in a way that uses homograph characters from other character sets, which facilitates phishing attacks.

Microsoft Internet Explorer 6.0 and possibly others allows remote attackers to upload arbitrary file contents when users press a key corresponding to the JavaScript (1) event.ctrlKey or (2) event.shiftKey onkeydown event contained in a webpage. NOTE: it was reported that the vendor has disputed the severity of this issue.

Opera 6.0.1 allows remote attackers to upload arbitrary file contents when users press a key corresponding to the JavaScript (1) event.ctrlKey or (2) event.shiftKey onkeydown event contained in a webpage.

Opera 6.0.3, when using Squid 2.4 for HTTPS proxying, does not properly handle when accepting a non-global certificate authority (CA) certificate from a site and establishing a subsequent HTTPS connection, which allows remote attackers to cause a denial of service (crash).

Cross-site scripting (XSS) vulnerability in the FTP view feature in Opera 6.0 and 6.01 through 6.04 allows remote attackers to inject arbitrary web script or HTML via the title tag of an FTP URL.

Buffer overflow in Opera 6.01 allows remote attackers to cause a denial of service (crash) via an IMG tag with large width and height attributes.

Opera 6.0.1 and 6.0.2 allows a remote web site to upload arbitrary files from the client system, without prompting the client, via an input type=file tag whose value contains a newline.

Netscape 6.2.3 and earlier, and Mozilla 1.0.1, allow remote attackers to corrupt heap memory and execute arbitrary code via a GIF image with a zero width.

Opera 6.01, 6.0, and 5.12 allows remote attackers to execute arbitrary JavaScript in the security context of other sites by setting the location of a frame or iframe to a Javascript: URL.

Opera, when configured with the "Determine action by MIME type" option disabled, interprets an object as an HTML document even when its MIME Content-Type is text/plain, which could allow remote attackers to execute arbitrary script in documents that the user does not expect, possibly through web applications that use a text/plain type to prevent cross-site scripting attacks.