diff --git a/CMakeLists.txt b/CMakeLists.txt
index ef4adf90..a8c28e99 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -45,7 +45,7 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DQT_NO_DEPRECATED_WARNINGS=Y")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DQT_DISABLE_DEPRECATED_BEFORE=0x050C00")
 
 # set CXXFLAGS for build targets
-set(CMAKE_CXX_FLAGS_DEBUG "-O1 ${CMAKE_CXX_FLAGS}")
+set(CMAKE_CXX_FLAGS_DEBUG "-O2 -D_FORTIFY_SOURCE=2 ${CMAKE_CXX_FLAGS}")
 set(CMAKE_CXX_FLAGS_RELEASE "-O2 -D_FORTIFY_SOURCE=2 ${CMAKE_CXX_FLAGS}")
 
 option(ENABLE_LTO "Enable Link Time Optimization" off)