protect_url_parameter is supposed to be used. Also modify the function comment for protect_url_parameter, _protect_url_parameter, and comment in global2.php against INPUT_FILTER_MODSECURITY_URL_PARAMETER, to also mention browser reflected-XSS filtering.
I added several missing protect_url_parameter but I cannot consider this issue resolved because top_login was not one of them from which this issue originates.
top_login gets login URL (+ redirect) from global3.php get_login_url but this is already using protect_url_parameter. So there is another bug somewhere.
top_login gets login URL (+ redirect) from global3.php get_login_url but this is already using protect_url_parameter. So there is another bug somewhere.