diff --git a/sys/netgraph/bluetooth/drivers/ubt/ng_ubt.c b/sys/netgraph/bluetooth/drivers/ubt/ng_ubt.c
--- a/sys/netgraph/bluetooth/drivers/ubt/ng_ubt.c
+++ b/sys/netgraph/bluetooth/drivers/ubt/ng_ubt.c
@@ -534,6 +534,7 @@
  * Size of both command and response buffers are passed in length field of
  * corresponding structures in "Parameter Total Length" format i.e.
  * not including HCI packet headers.
+ * Expected event code must be placed into "Event code" of the response buffer.
  *
  * Must not be used after USB transfers have been configured in attach routine.
  */
@@ -572,6 +573,12 @@
 	if (evt == NULL)
 		return (USB_ERR_NORMAL_COMPLETION);
 
+	/* Save operation code if we expect completion event in response */
+	if(((struct ubt_hci_event *)evt)->header.event ==
+	    NG_HCI_EVENT_COMMAND_COMPL)
+		((struct ubt_hci_event_command_compl *)evt)->opcode =
+		  cmd->opcode;
+
 	/* Initialize INTR endpoint xfer and wait for response */
 	mtx_init(&mtx, "ubt pb", NULL, MTX_DEF | MTX_NEW);
 
@@ -842,6 +849,8 @@
 	struct ubt_hci_event	*evt = usbd_xfer_softc(xfer);
 	struct usb_page_cache	*pc;
 	int			actlen;
+	struct ubt_hci_evhdr	evhdr;
+	uint16_t		opcode;
 
 	usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);
 
@@ -849,7 +858,25 @@
 	case USB_ST_TRANSFERRED:
 		if (actlen > UBT_HCI_EVENT_SIZE(evt))
 			actlen = UBT_HCI_EVENT_SIZE(evt);
+		if (actlen < sizeof(evhdr))
+			goto submit_next;
 		pc = usbd_xfer_get_frame(xfer, 0);
+		usbd_copy_out(pc, 0, &evhdr, sizeof(evhdr));
+		/* Check for expected event code */
+		if (evt->header.event != 0 &&
+		    (evt->header.event != evhdr.event))
+			goto submit_next;
+		/* For completion events check operation code as well */
+		if (evt->header.event == NG_HCI_EVENT_COMMAND_COMPL) {
+			if (actlen < sizeof(struct ubt_hci_event_command_compl))
+				goto submit_next;
+			usbd_copy_out(pc,
+			    offsetof(struct ubt_hci_event_command_compl, opcode),
+			    &opcode, sizeof(opcode));
+			if (opcode !=
+			    ((struct ubt_hci_event_command_compl *)evt)->opcode)
+				goto submit_next;
+		}
 		usbd_copy_out(pc, 0, evt, actlen);
 		/* OneShot mode */
 		wakeup(evt);
diff --git a/sys/netgraph/bluetooth/drivers/ubt/ng_ubt_intel.c b/sys/netgraph/bluetooth/drivers/ubt/ng_ubt_intel.c
--- a/sys/netgraph/bluetooth/drivers/ubt/ng_ubt_intel.c
+++ b/sys/netgraph/bluetooth/drivers/ubt/ng_ubt_intel.c
@@ -117,14 +117,14 @@
 	cmd.opcode = htole16(opcode);
 	evt = malloc(offsetof(struct ubt_hci_event_command_compl, data) +
 	    resp_len, M_TEMP, M_ZERO | M_WAITOK);
+	evt->header.event = NG_HCI_EVENT_COMMAND_COMPL;
 	evt->header.length = resp_len + UBT_HCI_EVENT_COMPL_HEAD_SIZE;
 
 	error = ubt_do_hci_request(udev, &cmd, evt, UBT_INTEL_HCICMD_TIMEOUT);
 	if (error != USB_ERR_NORMAL_COMPLETION)
 		goto exit;
 
-	if (evt->header.event == NG_HCI_EVENT_COMMAND_COMPL &&
-	    evt->header.length == resp_len + UBT_HCI_EVENT_COMPL_HEAD_SIZE)
+	if (evt->header.length == resp_len + UBT_HCI_EVENT_COMPL_HEAD_SIZE)
 		memcpy(resp, evt->data, resp_len);
 	else
 		error = USB_ERR_INVAL;
@@ -148,6 +148,7 @@
 	uint8_t *data;
 
 	evt = malloc(UBT_INTEL_MAX_EVT_SIZE, M_TEMP, M_ZERO | M_WAITOK);
+	evt->header.event = NG_HCI_EVENT_COMMAND_COMPL;
 	evt->header.length =
 	    UBT_INTEL_MAX_EVT_SIZE - sizeof(struct ubt_hci_evhdr);