This vulnerability allows an attacker to include remote files in the XT-Conteudo module for XOOPS CMS. The vulnerable code is located in the 'spaw_control.class.php' file, where it includes the 'spaw_control.config.php', 'toolbars.class.php', and 'lang.class.php' files without proper validation. An attacker can exploit this by providing a malicious URL as the 'spaw_root' parameter, leading to remote file inclusion and potential code execution.