static int cxusb_bluebird_gpio_rw(struct dvb_usb_device *d, u8 changemask,
				 u8 newval)
{
	u8 o[2], gpio_state;
	int rc;

	o[0] = 0xff & ~changemask;	/* mask of bits to keep */
	o[1] = newval & changemask;	/* new values for bits  */

	rc = cxusb_ctrl_msg(d, CMD_BLUEBIRD_GPIO_RW, o, 2, &gpio_state, 1);
	if (rc < 0 || (gpio_state & changemask) != (newval & changemask))
		deb_info("bluebird_gpio_write failed.\n");

	return rc < 0 ? rc : gpio_state;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.