diff --git a/USBDevice.py b/USBDevice.py
index c2142d5..d045407 100644
--- a/USBDevice.py
+++ b/USBDevice.py
@@ -380,7 +380,10 @@ def handle_get_descriptor_request(self, req):
             self.maxusb_app.stall_ep0()
 
     def handle_get_configuration_descriptor_request(self, num):
-        return self.configurations[num].get_descriptor()
+        if num < len(self.configurations):
+            return self.configurations[num].get_descriptor()
+        else:
+            return self.configurations[0].get_descriptor()
 
     def handle_get_string_descriptor_request(self, num):
         if num == 0: