diff --git a/apps/app_celgenuserevent.c b/apps/app_celgenuserevent.c
index 25065dccb26e3a9ab746bcf27858ee2f29965f60..871724679cb7663452c3fa00720c2e506ebd3afb 100644
--- a/apps/app_celgenuserevent.c
+++ b/apps/app_celgenuserevent.c
@@ -77,7 +77,7 @@ static int celgenuserevent_exec(struct ast_channel *chan, const char *data)
 
 	blob = ast_json_pack("{s: s, s: {s: s}}",
 		"event", args.event,
-		"extra", "extra", args.extra);
+		"extra", "extra", S_OR(args.extra, ""));
 	if (!blob) {
 		return res;
 	}