Index: lib/libusb/libusb.h
===================================================================
--- lib/libusb/libusb.h
+++ lib/libusb/libusb.h
@@ -388,6 +388,7 @@
 	uint8_t bNumDeviceCapabilities;
 	struct libusb_usb_2_0_device_capability_descriptor *usb_2_0_ext_cap;
 	struct libusb_ss_usb_device_capability_descriptor *ss_usb_cap;
+	struct libusb_bos_dev_capability_descriptor *dev_capability;
 }	libusb_bos_descriptor __aligned(sizeof(void *));
 
 typedef struct libusb_usb_2_0_extension_descriptor {
Index: lib/libusb/libusb10_desc.c
===================================================================
--- lib/libusb/libusb10_desc.c
+++ lib/libusb/libusb10_desc.c
@@ -470,6 +470,7 @@
 			ptr->bNumDeviceCapabilities = ((const uint8_t *)buf)[4];
 			ptr->usb_2_0_ext_cap = NULL;
 			ptr->ss_usb_cap = NULL;
+			ptr->dev_capability = NULL;
 
 			dcap_20 = (void *)(ptr + 1);
 			ss_cap = (void *)(dcap_20 + 1);
@@ -485,6 +486,15 @@
 					break;
 
 				ptr->usb_2_0_ext_cap = dcap_20;
+				/*
+				 * This assumes dcap_20 and ss_cap occupy a contiguous block of
+				 * memory, as allocated above. Should this change, this and the
+				 * later setting of ptr->dev_capability will need to be
+				 * re-evaluated.
+				 */
+				if (ptr->dev_capability == NULL ||
+				    (void *)ptr->dev_capability > (void *)dcap_20)
+					ptr->dev_capability = (struct libusb_bos_dev_capability_descriptor *)dcap_20;
 
 				dcap_20->bLength = LIBUSB_USB_2_0_EXTENSION_DEVICE_CAPABILITY_SIZE;
 				dcap_20->bDescriptorType = dtype;
@@ -502,6 +512,9 @@
 					break;
 
 				ptr->ss_usb_cap = ss_cap;
+				if (ptr->dev_capability == NULL ||
+				    (void *)ptr->dev_capability > (void *)ss_cap)
+					ptr->dev_capability = (struct libusb_bos_dev_capability_descriptor *)ss_cap;
 
 				ss_cap->bLength = LIBUSB_SS_USB_DEVICE_CAPABILITY_SIZE;
 				ss_cap->bDescriptorType = dtype;