            $def = new HTMLPurifier_URIDefinition();
        } else {
            throw new HTMLPurifier_Exception("Definition of $type type not supported");
        }
        $this->definitions[$type] = $def;
        return $def;
    }
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.