Thomas Waldegger has reported some vulnerabilities in Wordpress, which can be exploited by malicious people to conduct cross-site scripting and script insertion attacks.

1) Input passed to certain parameters in various scripts isn't properly verified before it is returned to the user. This can be exploited to execute arbitrary HTML or script code in a user's browser session in context of an affected site by tricking the user into visiting a malicious website or follow a specially crafted link.

Examples:
http://[victim]/wp-login.php?redirect_to=[code]
http://[victim]/wp-login.php?mode=bookmarklet&text=[code]
http://[victim]/wp-login.php?mode=bookmarklet&popupurl=[code]
http://[victim]/wp-login.php?mode=bookmarklet&popuptitle=[code]
http://[victim]/admin-header.php?redirect=1&redirect_url=%22;[code]//
http://[victim]/bookmarklet.php?popuptitle=[code]
http://[victim]/bookmarklet.php?popupurl=[code]]
http://[victim]/bookmarklet.php?content=[code]
http://[victim]/bookmarklet.php?post_title=[code]
http://[victim]/categories.php?action=edit&cat_ID=[code]
http://[victim]/edit.php?s=[code]
http://[victim]/edit-comments.php?s=[code]
http://[victim]/edit-comments.php?mode=[code]

2) Input passed when posting messages, adding new categories and changing profile values is not properly sanitised before being used. This can be exploited to inject arbitrary HTML and script code, which will be executed in a user's browser session in context of an affected site when the malicious user data is viewed.

Successful exploitation requires user to be an administrator or privileged user.

The vulnerabilities have been reported in version 1.2. Some vulnerabilities also exists in 1.2.2. Other versions may also be affected.

Solution
Use another product.

Provided and/or discovered by
Thomas Waldegger

Changelog
Further details available to Secunia VIM customers

Original Advisory
http://wordpress.org/development/2004/10/wp-121/

Deep Links
Links available to Secunia VIM customers