    private function _mergeAssocArray(&$a1, $a2) {
        foreach ($a2 as $k => $v) {
            if ($v === false) {
                if (isset($a1[$k])) unset($a1[$k]);
                continue;
            }
            $a1[$k] = $v;
        }
    }
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.