diff --git a/components/usb/private_include/usb_private.h b/components/usb/private_include/usb_private.h
index b245970b54..aaa34a1667 100644
--- a/components/usb/private_include/usb_private.h
+++ b/components/usb/private_include/usb_private.h
@@ -38,12 +38,13 @@ _Static_assert(sizeof(usb_transfer_dummy_t) == sizeof(usb_transfer_t), "usb_tran
 
 struct urb_s{
     TAILQ_ENTRY(urb_s) tailq_entry;
-    //HCD handler pointer and variables. Must be initialized to NULL and 0 respectively
+    //HCD Layer: Handler pointer and variables. Must be initialized to NULL and 0 respectively
     void *hcd_ptr;
     uint32_t hcd_var;
-    //Host Driver layer handler
+    //Host Lib Layer:
     void *usb_host_client;  //Currently only used when submitted to shared pipes (i.e., Device default pipes)
     size_t usb_host_header_size; //USB Host may need the data buffer to have a transparent header
+    bool usb_host_inflight; //Debugging variable, used to prevent re-submitting URBs already inflight
     //Public transfer structure. Must be last due to variable length array
     usb_transfer_t transfer;
 };
diff --git a/components/usb/test/usb_host/msc_client_async_seq.c b/components/usb/test/usb_host/msc_client_async_seq.c
index d4be014b1c..16ce7bd3c4 100644
--- a/components/usb/test/usb_host/msc_client_async_seq.c
+++ b/components/usb/test/usb_host/msc_client_async_seq.c
@@ -192,6 +192,8 @@ void msc_client_async_seq_task(void *arg)
                 xfer_out->num_bytes = sizeof(usb_setup_packet_t);
                 xfer_out->bEndpointAddress = 0;
                 TEST_ASSERT_EQUAL(ESP_OK, usb_host_transfer_submit_control(msc_obj.client_hdl, xfer_out));
+                //Test that an inflight control transfer cannot be resubmitted
+                TEST_ASSERT_EQUAL(ESP_ERR_NOT_FINISHED, usb_host_transfer_submit_control(msc_obj.client_hdl, xfer_out));
                 //Next stage set from transfer callback
                 break;
             }
@@ -201,6 +203,8 @@ void msc_client_async_seq_task(void *arg)
                 xfer_out->num_bytes = sizeof(mock_msc_bulk_cbw_t);
                 xfer_out->bEndpointAddress = MOCK_MSC_SCSI_BULK_OUT_EP_ADDR;
                 TEST_ASSERT_EQUAL(ESP_OK, usb_host_transfer_submit(xfer_out));
+                //Test that an inflight transfer cannot be resubmitted
+                TEST_ASSERT_EQUAL(ESP_ERR_NOT_FINISHED, usb_host_transfer_submit(xfer_out));
                 //Next stage set from transfer callback
                 break;
             }
@@ -209,6 +213,8 @@ void msc_client_async_seq_task(void *arg)
                 xfer_in->num_bytes = usb_round_up_to_mps(MOCK_MSC_SCSI_SECTOR_SIZE * msc_obj.test_param.num_sectors_per_xfer, MOCK_MSC_SCSI_BULK_EP_MPS);
                 xfer_in->bEndpointAddress = MOCK_MSC_SCSI_BULK_IN_EP_ADDR;
                 TEST_ASSERT_EQUAL(ESP_OK, usb_host_transfer_submit(xfer_in));
+                //Test that an inflight transfer cannot be resubmitted
+                TEST_ASSERT_EQUAL(ESP_ERR_NOT_FINISHED, usb_host_transfer_submit(xfer_in));
                 //Next stage set from transfer callback
                 break;
             }
@@ -217,6 +223,8 @@ void msc_client_async_seq_task(void *arg)
                 xfer_in->num_bytes = usb_round_up_to_mps(sizeof(mock_msc_bulk_csw_t), MOCK_MSC_SCSI_BULK_EP_MPS);
                 xfer_in->bEndpointAddress = MOCK_MSC_SCSI_BULK_IN_EP_ADDR;
                 TEST_ASSERT_EQUAL(ESP_OK, usb_host_transfer_submit(xfer_in));
+                //Test that an inflight transfer cannot be resubmitted
+                TEST_ASSERT_EQUAL(ESP_ERR_NOT_FINISHED, usb_host_transfer_submit(xfer_in));
                 //Next stage set from transfer callback
                 break;
             }
diff --git a/components/usb/usb_host.c b/components/usb/usb_host.c
index 2c8531e7c2..ebbb00b33c 100644
--- a/components/usb/usb_host.c
+++ b/components/usb/usb_host.c
@@ -438,8 +438,8 @@ assign_err:
 hub_err:
     ESP_ERROR_CHECK(usbh_uninstall());
 usbh_err:
-    if (p_host_lib_obj->constant.phy_handle) {
-        ESP_ERROR_CHECK(usb_del_phy(p_host_lib_obj->constant.phy_handle));
+    if (host_lib_obj->constant.phy_handle) {
+        ESP_ERROR_CHECK(usb_del_phy(host_lib_obj->constant.phy_handle));
     }
 phy_err:
 alloc_err:
@@ -591,6 +591,8 @@ static void _handle_pending_ep(client_t *client_obj)
                 //Dequeue all URBs and run their transfer callback
                 urb_t *urb = hcd_urb_dequeue(ep_obj->constant.pipe_hdl);
                 while (urb != NULL) {
+                    //Clear the transfer's inflight flag to indicate the transfer is no longer inflight
+                    urb->usb_host_inflight = false;
                     urb->transfer.callback(&urb->transfer);
                     num_urb_dequeued++;
                     urb = hcd_urb_dequeue(ep_obj->constant.pipe_hdl);
@@ -748,6 +750,8 @@ esp_err_t usb_host_client_handle_events(usb_host_client_handle_t client_hdl, Tic
             TAILQ_REMOVE(&client_obj->dynamic.done_ctrl_xfer_tailq, urb, tailq_entry);
             client_obj->dynamic.num_done_ctrl_xfer--;
             HOST_EXIT_CRITICAL();
+            //Clear the transfer's inflight flag to indicate the transfer is no longer inflight
+            urb->usb_host_inflight = false;
             //Call the transfer's callback
             urb->transfer.callback(&urb->transfer);
             HOST_ENTER_CRITICAL();
@@ -1298,6 +1302,9 @@ esp_err_t usb_host_transfer_submit(usb_transfer_t *transfer)
                               USB_EP_DESC_GET_XFERTYPE(ep_obj->constant.ep_desc),
                               USB_EP_DESC_GET_MPS(ep_obj->constant.ep_desc),
                               transfer->bEndpointAddress & USB_B_ENDPOINT_ADDRESS_EP_DIR_MASK), ESP_ERR_INVALID_ARG);
+    //Check that we are not submitting a transfer already inflight
+    HOST_CHECK(!urb_obj->usb_host_inflight, ESP_ERR_NOT_FINISHED);
+    urb_obj->usb_host_inflight = true;
     HOST_ENTER_CRITICAL();
     ep_obj->dynamic.num_urb_inflight++;
     HOST_EXIT_CRITICAL();
@@ -1317,6 +1324,7 @@ hcd_err:
     HOST_ENTER_CRITICAL();
     ep_obj->dynamic.num_urb_inflight--;
     HOST_EXIT_CRITICAL();
+    urb_obj->usb_host_inflight = false;
 err:
     return ret;
 }
@@ -1324,6 +1332,7 @@ err:
 esp_err_t usb_host_transfer_submit_control(usb_host_client_handle_t client_hdl, usb_transfer_t *transfer)
 {
     HOST_CHECK(client_hdl != NULL && transfer != NULL, ESP_ERR_INVALID_ARG);
+
     //Check that control transfer is valid
     HOST_CHECK(transfer->device_handle != NULL, ESP_ERR_INVALID_ARG);   //Target device must be set
     usb_device_handle_t dev_hdl = transfer->device_handle;
@@ -1333,8 +1342,18 @@ esp_err_t usb_host_transfer_submit_control(usb_host_client_handle_t client_hdl,
     HOST_CHECK(transfer_check(transfer, USB_TRANSFER_TYPE_CTRL, dev_info.bMaxPacketSize0, xfer_is_in), ESP_ERR_INVALID_ARG);
     //Control transfers must be targeted at EP 0
     HOST_CHECK((transfer->bEndpointAddress & USB_B_ENDPOINT_ADDRESS_EP_NUM_MASK) == 0, ESP_ERR_INVALID_ARG);
-    //Save client handle into URB
+
     urb_t *urb_obj = __containerof(transfer, urb_t, transfer);
+    //Check that we are not submitting a transfer already inflight
+    HOST_CHECK(!urb_obj->usb_host_inflight, ESP_ERR_NOT_FINISHED);
+    urb_obj->usb_host_inflight = true;
+    //Save client handle into URB
     urb_obj->usb_host_client = (void *)client_hdl;
-    return usbh_dev_submit_ctrl_urb(dev_hdl, urb_obj);
+
+    esp_err_t ret;
+    ret = usbh_dev_submit_ctrl_urb(dev_hdl, urb_obj);
+    if (ret != ESP_OK) {
+        urb_obj->usb_host_inflight = false;
+    }
+    return ret;
 }
diff --git a/components/usb/usbh.c b/components/usb/usbh.c
index 6426e16c8f..aad2f54def 100644
--- a/components/usb/usbh.c
+++ b/components/usb/usbh.c
@@ -536,7 +536,7 @@ esp_err_t usbh_dev_open(uint8_t dev_addr, usb_device_handle_t *dev_hdl)
             goto exit;
         }
     }
-    TAILQ_FOREACH(dev_obj, &p_usbh_obj->dynamic.devs_idle_tailq, dynamic.tailq_entry) {
+    TAILQ_FOREACH(dev_obj, &p_usbh_obj->dynamic.devs_pending_tailq, dynamic.tailq_entry) {
         if (dev_obj->constant.address == dev_addr) {
             found_dev_obj = dev_obj;
             goto exit;
@@ -783,7 +783,7 @@ esp_err_t usbh_ep_alloc(usb_device_handle_t dev_hdl, usbh_ep_config_t *ep_config
     if (is_in && dev_obj->mux_protected.ep_in[addr - 1] == NULL) {  //Is an IN EP
         dev_obj->mux_protected.ep_in[addr - 1] = pipe_hdl;
         assigned = true;
-    } else if (dev_obj->mux_protected.ep_out[addr - 1] == NULL) {   //Is an OUT EP
+    } else if (!is_in && dev_obj->mux_protected.ep_out[addr - 1] == NULL) {   //Is an OUT EP
         dev_obj->mux_protected.ep_out[addr - 1] = pipe_hdl;
         assigned = true;
     }