A vulnerability has been found in MaxSite CMS up to 109.3. This issue affects some unknown processing of the component Guestbook Plugin. Such manipulation of the argument f_text/f_slug/f_limit/f_email leads to cross site scripting. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 109.4 is capable of addressing this issue. The name of the patch is 8a3946bd0a54bfb72a4d57179fcd253f2c550cd7. It is suggested to upgrade the affected component. The vendor was informed early about this issue. They classify it as a "Self-XSS". They deployed a countermeasure: "Nevertheless, we consider this a violation of secure coding standards. The lack of filtering via `htmlspecialchars()` has already been fixed in the latest patch to prevent incorrect data display."