Code:  static int mct_u232_port_probe(struct usb_serial_port *port)
 {
 	struct mct_u232_private *priv;
 
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
 	/* Use second interrupt-in endpoint for reading. */
	priv->read_urb = port->serial->port[1]->interrupt_in_urb;
 	priv->read_urb->context = port;
 
 	spin_lock_init(&priv->lock);

	usb_set_serial_port_data(port, priv);

	return 0;
}

Vulnerability Type: DoS 
CWE ID: 
Summary: The mct_u232_msr_to_state function in drivers/usb/serial/mct_u232.c in the Linux kernel before 4.5.1 allows physically proximate attackers to cause a denial of service (NULL pointer dereference and system crash) via a crafted USB device without two interrupt-in endpoint descriptors.
Commit Message: USB: mct_u232: add sanity checking in probe

An attack using the lack of sanity checking in probe is known. This
patch checks for the existence of a second port.

CVE-2016-3136

Signed-off-by: Oliver Neukum <ONeukum@suse.com>
CC: stable@vger.kernel.org
[johan: add error message ]
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>