diff --git a/devicemodel/hw/pci/xhci.c b/devicemodel/hw/pci/xhci.c
index cf7485c4b..80b3d7576 100644
--- a/devicemodel/hw/pci/xhci.c
+++ b/devicemodel/hw/pci/xhci.c
@@ -2523,9 +2523,10 @@ done:
 	return cmderr;
 }
 
-#define XHCI_GET_SLOT(xdev, trb, slot, cmderr)			\
+#define XHCI_GET_SLOT(xdev, trb, slot, cmderr)				\
 	do {								\
-		slot = (XHCI_TRB_3_SLOT_GET(trb->dwTrb3)) ? 0 :		\
+		slot = (XHCI_TRB_3_SLOT_GET(trb->dwTrb3) > 		\
+			XHCI_MAX_SLOTS) ? 0 :				\
 			XHCI_TRB_3_SLOT_GET(trb->dwTrb3);		\
 		if (!slot)						\
 			cmderr = XHCI_TRB_ERROR_INVALID;		\