diff --git a/net/tcp/tcp_send.c b/net/tcp/tcp_send.c
index ae231b161e..041b07fc1a 100644
--- a/net/tcp/tcp_send.c
+++ b/net/tcp/tcp_send.c
@@ -477,7 +477,7 @@ void tcp_reset(FAR struct net_driver_s *dev, FAR struct tcp_conn_s *conn)
 
       ipv6_build_header(ipv6, dev->d_len - IPv6_HDRLEN,
                         IP_PROTO_TCP, dev->d_ipv6addr, ipv6->srcipaddr,
-                        IP_TTL_DEFAULT, conn->sconn.s_tclass);
+                        IP_TTL_DEFAULT, conn ? conn->sconn.s_tclass : 0);
 
       tcp->tcpchksum = 0;
       tcp->tcpchksum = ~tcp_ipv6_chksum(dev);
@@ -493,7 +493,7 @@ void tcp_reset(FAR struct net_driver_s *dev, FAR struct tcp_conn_s *conn)
 
       ipv4_build_header(IPv4BUF, dev->d_len, IP_PROTO_TCP,
                         &dev->d_ipaddr, (FAR in_addr_t *)ipv4->srcipaddr,
-                        IP_TTL_DEFAULT, conn->sconn.s_tos, NULL);
+                        IP_TTL_DEFAULT, conn ? conn->sconn.s_tos : 0, NULL);
 
       tcp->tcpchksum = 0;
       tcp->tcpchksum = ~tcp_ipv4_chksum(dev);