Secunia

r0ut3r has discovered some vulnerabilities in Extreme CMS, which can be exploited by malicious users to conduct script insertion attacks and by malicious people to bypass certain security restrictions.

1) Input passed to the "bg1", "bg2", "text", and "size" form field parameters in admin/options.php is not properly sanitised before being used. This can be exploited to insert arbitrary HTML and script code, which will be executed in a user's browser session in context of an affected site when the malicious data is viewed.

2) It is possible to access admin/options.php without proper authentication. In combination with vulnerability #1 this can e.g. be exploited by an unauthenticated person to conduct script insertion attacks.

The vulnerabilities are confirmed in version 0.9. Other versions may also be affected.

Solution
Edit the source code to ensure that input is properly sanitised and restrict access to the "admin" directory e.g. with an ".htaccess" file.

Provided and/or discovered by
r0ut3r

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