Language: PHP
Label: safe
CWE: CWE-79 \u2014 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Code:
    public function addFilter($filter)
    {
        trigger_error(
            'HTMLPurifier->addFilter() is deprecated, use configuration directives' .
            ' in the Filter namespace or Filter.Custom',
            E_USER_WARNING
        );
        $this->filters[] = $filter;
    }