    public function validate($string, $config, $context) {
        $string = $this->parseCDATA($string);
        if ($string === '') return false;
        $parts = explode(' ', $string); // parseCDATA replaced \r, \t and \n
        $length = count($parts);
        $final = '';
        for ($i = 0, $num = 0; $i < $length && $num < $this->max; $i++) {
            if (ctype_space($parts[$i])) continue;
            $result = $this->single->validate($parts[$i], $config, $context);
            if ($result !== false) {
                $final .= $result . ' ';
                $num++;
            }
        }
        if ($final === '') return false;
        return rtrim($final);
    }
The software 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.