diff --git a/lib/secure-streams/secure-streams-serialize.c b/lib/secure-streams/secure-streams-serialize.c
index 75c5ac79a..0b128eb39 100644
--- a/lib/secure-streams/secure-streams-serialize.c
+++ b/lib/secure-streams/secure-streams-serialize.c
@@ -132,6 +132,8 @@ lws_ss_serialize_rx_payload(struct lws_dsh *dsh, const uint8_t *buf,
 		 * on a non-default rideshare
 		 */
 		assert(rsp);
+		if (!rsp)
+			return 1;
 		l = strlen(rsp);
 		est += 1 + l;
 	} else