diff --git a/sys/netinet/sctp_output.c b/sys/netinet/sctp_output.c
index d7742222a3b..c988a8426fe 100644
--- a/sys/netinet/sctp_output.c
+++ b/sys/netinet/sctp_output.c
@@ -5039,11 +5039,16 @@ sctp_arethere_unrecognized_parameters(struct mbuf *in_initpkt,
 			at += padded_size;
 			break;
 		case SCTP_HAS_NAT_SUPPORT:
+			if (padded_size != sizeof(struct sctp_paramhdr)) {
+				SCTPDBG(SCTP_DEBUG_OUTPUT1, "Invalid size - error nat support %d\n", plen);
+				goto invalid_size;
+			}
 			*nat_friendly = 1;
-			/* FALLTHROUGH */
+			at += padded_size;
+			break;
 		case SCTP_PRSCTP_SUPPORTED:
 			if (padded_size != sizeof(struct sctp_paramhdr)) {
-				SCTPDBG(SCTP_DEBUG_OUTPUT1, "Invalid size - error prsctp/nat support %d\n", plen);
+				SCTPDBG(SCTP_DEBUG_OUTPUT1, "Invalid size - error prsctp %d\n", plen);
 				goto invalid_size;
 			}
 			at += padded_size;