Cross-site Scripting in M4 PDF plugin for Prestashop sites

M4 PDF plugin for Prestashop sites, in its 3.2.3 version and before, is vulnerable to an arbitrary HTML Document crafting vulnerability. The resource /m4pdf/pdf.php uses templates to dynamically create documents. In the case that the template does not exist, the application will return a fixed document with a message in mpdf format. An attacker could exploit this vulnerability by inputting a valid HTML/CSS document as the value of the parameter.