diff --git a/examples/mcast_udp_server/mcast_udp_server.c b/examples/mcast_udp_server/mcast_udp_server.c
index 6cbc7983..56884582 100644
--- a/examples/mcast_udp_server/mcast_udp_server.c
+++ b/examples/mcast_udp_server/mcast_udp_server.c
@@ -79,7 +79,7 @@ int main(int argc, char **argv) {
   mg_mgr_init(&mgr, NULL);
   {
     char listen[256];
-    sprintf(listen, "udp://%s", port);
+    snprintf(listen, sizeof(listen), "udp://%s", port);
     nc = mg_bind(&mgr, listen, ev_handler);
   }