diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index a8090378c..c99b29aed 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -5,7 +5,7 @@ option(JSON_NoExceptions "Build test suite without exceptions" OFF)
 if(JSON_Sanitizer)
     message(STATUS "Building test suite with Clang sanitizer")
     if(NOT MSVC)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -O2 -fsanitize=address -fsanitize=undefined -fno-omit-frame-pointer")
+        set(CMAKE_CXX_FLAGS "-g -O2 -fsanitize=address -fsanitize=undefined -fno-omit-frame-pointer")
     endif()
 endif()