Input validation vulnerability in Co-marquage service-public.fr 0.5.76

The Co-marquage service-public.fr plugin for WordPress has a security issue known as Reflected Cross-Site Scripting. This is because the plugin uses a function called add_query_arg without properly protecting the URL. This vulnerability exists in all versions of the plugin up to and including 0.5.76. As a result, attackers who are not logged in can inject harmful code into web pages. This can happen if they trick a user into clicking on a link.