    public function __construct() {
        $this->ipv4 = new HTMLPurifier_AttrDef_URI_IPv4();
        $this->ipv6 = new HTMLPurifier_AttrDef_URI_IPv6();
    }
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.