diff --git a/src/http.c b/src/http.c
index 51f95f4..ea70511 100644
--- a/src/http.c
+++ b/src/http.c
@@ -248,7 +248,7 @@ static void _http_callback_root(struct evhttp_request *request, UNUSED void *arg
 	PROCESS_HEAD_REQUEST;
 
 	assert((buf = evbuffer_new()));
-	assert(evbuffer_add_printf(buf, HTML_INDEX_PAGE));
+	assert(evbuffer_add_printf(buf, "%s", HTML_INDEX_PAGE));
 	ADD_HEADER("Content-Type", "text/html");
 	evhttp_send_reply(request, HTTP_OK, "OK", buf);
 	evbuffer_free(buf);