diff --git a/lib/client-parser.c b/lib/client-parser.c
index d7b97cc3..2dabeffc 100644
--- a/lib/client-parser.c
+++ b/lib/client-parser.c
@@ -214,8 +214,10 @@ int libwebsocket_client_rx_sm(struct libwebsocket *wsi, unsigned char c)
 
 	case LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED:
 
-		if (!wsi->u.ws.rx_user_buffer)
+		if (!wsi->u.ws.rx_user_buffer) {
 			lwsl_err("NULL client rx_user_buffer\n");
+			return 1;
+		}
 
 		if ((!wsi->u.ws.this_frame_masked) || wsi->u.ws.all_zero_nonce)
 			wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +