diff --git a/netgraph7/netgraph/ng_base.c b/netgraph7/netgraph/ng_base.c
--- a/netgraph7/netgraph/ng_base.c
+++ b/netgraph7/netgraph/ng_base.c
@@ -922,6 +922,8 @@
 	|| (val == 0)) {
 		return ((ng_ID_t)0);
 	}
+	if (val > NG_NODES)
+		return ((ng_ID_t)0);
 	return (ng_ID_t)val;
 }