diff --git a/pkg/lwip/contrib/sock/ip/lwip_sock_ip.c b/pkg/lwip/contrib/sock/ip/lwip_sock_ip.c
index fde43b4d43..d9d79923c5 100644
--- a/pkg/lwip/contrib/sock/ip/lwip_sock_ip.c
+++ b/pkg/lwip/contrib/sock/ip/lwip_sock_ip.c
@@ -174,7 +174,7 @@ ssize_t sock_ip_send(sock_ip_t *sock, const void *data, size_t len,
 {
     assert((sock != NULL) || (remote != NULL));
     assert((len == 0) || (data != NULL)); /* (len != 0) => (data != NULL) */
-    return lwip_sock_send(&sock->conn, data, len, proto,
+    return lwip_sock_send(sock ? &sock->conn : NULL, data, len, proto,
                           (struct _sock_tl_ep *)remote, NETCONN_RAW);
 }
 
diff --git a/pkg/lwip/contrib/sock/udp/lwip_sock_udp.c b/pkg/lwip/contrib/sock/udp/lwip_sock_udp.c
index e947849857..e16b4bbae8 100644
--- a/pkg/lwip/contrib/sock/udp/lwip_sock_udp.c
+++ b/pkg/lwip/contrib/sock/udp/lwip_sock_udp.c
@@ -128,8 +128,8 @@ ssize_t sock_udp_send(sock_udp_t *sock, const void *data, size_t len,
     if ((remote != NULL) && (remote->port == 0)) {
         return -EINVAL;
     }
-    return lwip_sock_send(&sock->conn, data, len, 0, (struct _sock_tl_ep *)remote,
-                          NETCONN_UDP);
+    return lwip_sock_send((sock) ? &sock->conn : NULL, data, len, 0,
+                          (struct _sock_tl_ep *)remote, NETCONN_UDP);
 }
 
 /** @} */