diff --git a/nimble/host/src/ble_hs_flow.c b/nimble/host/src/ble_hs_flow.c
index 1f3e4eee8..c0f9f5097 100644
--- a/nimble/host/src/ble_hs_flow.c
+++ b/nimble/host/src/ble_hs_flow.c
@@ -82,7 +82,7 @@ ble_hs_flow_tx_num_comp_pkts(void)
             rc = ble_hs_hci_cmd_send_buf(
                 BLE_HCI_OP(BLE_HCI_OGF_CTLR_BASEBAND,
                            BLE_HCI_OCF_CB_HOST_NUM_COMP_PKTS),
-                buf, off);
+                buf, sizeof(buf));
             if (rc != 0) {
                 return rc;
             }