The SQL Chart Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'X-axis column value ($value->$xarg_s from $wpdb->get_results())' parameter in all versions up to, and including, 3.0.6 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires an administrator to have published a chart whose SQL query returns a column controllable by a lower-privileged user, such as wp_users.display_name, which a Subscriber can populate with a payload via the standard WordPress profile page at /wp-admin/profile.php.