diff --git a/CMakeLists.txt b/CMakeLists.txt
index a35d91aaa..9c699ca93 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,6 +4,7 @@ cmake_minimum_required(VERSION 2.8.8)
 set(BOOST_MIN_VERSION "1.66.0")
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
 
 project(icinga2)
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")