Index: sys/netgraph/ng_parse.c
===================================================================
--- sys/netgraph/ng_parse.c
+++ sys/netgraph/ng_parse.c
@@ -1208,6 +1208,10 @@
 	int align, len, blen, error = 0;
 
 	/* Initialize */
+	if (num < 0) {
+		error = EINVAL;
+		goto done;
+	}
 	foff = malloc(num * sizeof(*foff), M_NETGRAPH_PARSE, M_NOWAIT | M_ZERO);
 	if (foff == NULL) {
 		error = ENOMEM;