--- a/sys/netinet6/in6_proto.c
+++ b/sys/netinet6/in6_proto.c
@@ -446,7 +446,7 @@ static int
 	old = ip6_temp_valid_lifetime;
 	error = SYSCTL_IN(req, arg1, sizeof(int));
 	if (ip6_temp_valid_lifetime < ip6_temp_preferred_lifetime) {
-		ip6_temp_preferred_lifetime = old;
+		ip6_temp_valid_lifetime = old;
 		return (EINVAL);
 	}
 	return (error);