static int cxusb_ctrl_msg(struct dvb_usb_device *d,
 			  u8 cmd, u8 *wbuf, int wlen, u8 *rbuf, int rlen)
 {
 	struct cxusb_state *st = d->priv;
	int ret;
 
 	if (1 + wlen > MAX_XFER_SIZE) {
 		warn("i2c wr: len=%d is too big!\n", wlen);
 		return -EOPNOTSUPP;
 	}
 
	if (rlen > MAX_XFER_SIZE) {
		warn("i2c rd: len=%d is too big!\n", rlen);
		return -EOPNOTSUPP;
	}
 
 	mutex_lock(&d->data_mutex);
 	st->data[0] = cmd;
 	memcpy(&st->data[1], wbuf, wlen);
	ret = dvb_usb_generic_rw(d, st->data, 1 + wlen, st->data, rlen, 0);
	if (!ret && rbuf && rlen)
		memcpy(rbuf, st->data, rlen);
 
 	mutex_unlock(&d->data_mutex);
 	return ret;
}

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.