diff --git a/netinet6/ip6_input.c b/netinet6/ip6_input.c
--- a/netinet6/ip6_input.c
+++ b/netinet6/ip6_input.c
@@ -690,7 +690,7 @@
 	while (nxt != IPPROTO_DONE) {
 		struct protosw *sw6;
 
-		if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
+		if (++nest > (ip6_hdrnestlimit ? ip6_hdrnestlimit : 64)) {
 			ip6stat.ip6s_toomanyhdr++;
 			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
 			goto bad;