diff --git a/sys/net/netmap/netmap_vale.c b/sys/net/netmap/netmap_vale.c
--- a/sys/net/netmap/netmap_vale.c
+++ b/sys/net/netmap/netmap_vale.c
@@ -1696,7 +1696,7 @@
 		}
 
 		/* cross-link the netmap rings */
-		for (i = 0; i <= na->num_tx_rings; i++) {
+		for (i = 0; i <= hwna->num_tx_rings && i <= na->num_tx_rings; i++) {
 			hwna->tx_rings[i].nkr_num_slots = na->rx_rings[i].nkr_num_slots;
 			hwna->tx_rings[i].ring = na->rx_rings[i].ring;
 		}