The FTP protocol implementation in Opera 9.10 allows remote attackers to allows remote servers to force the client to connect to other servers, perform a proxied port scan, or obtain sensitive information by specifying an alternate server address in an FTP PASV response.

The child frames in Opera 9 before 9.20 inherit the default charset from the parent window when a charset is not specified in an HTTP Content-Type header or META tag, which allows remote attackers to conduct cross-site scripting (XSS) attacks, as demonstrated using the UTF-7 character set.

Opera 9.10 Final allows remote attackers to bypass the Fraud Protection mechanism by adding certain characters to the end of a domain name, as demonstrated by the "." and "/" characters, which is not caught by the blacklist filter.

Mozilla Firefox 2.0.0.1 allows remote attackers to bypass the Phishing Protection mechanism by adding certain characters to the end of the domain name, as demonstrated by the "." and "/" characters, which is not caught by the Phishing List blacklist filter.

Opera allows remote attackers to cause a denial of service (application crash) via a web page that contains a large number of nested marquee tags, a related issue to CVE-2006-2723.