void usb_release_interface_cache(struct kref *ref)
{
	struct usb_interface_cache *intfc = ref_to_usb_interface_cache(ref);
	int j;

	for (j = 0; j < intfc->num_altsetting; j++) {
		struct usb_host_interface *alt = &intfc->altsetting[j];

		kfree(alt->endpoint);
		kfree(alt->string);
	}
	kfree(intfc);
}

The product reads data past the end, or before the beginning, of the intended buffer.