--- a/cmake/modules/DefineCompilerFlags.cmake

+++ b/cmake/modules/DefineCompilerFlags.cmake

@@ -48,9 +48,9 @@ if (${CMAKE_C_COMPILER_ID} MATCHES "(GNU|Clang)")

     if (CMAKE_BUILD_TYPE)

         string(TOLOWER "${CMAKE_BUILD_TYPE}" CMAKE_BUILD_TYPE_LOWER)

         if (CMAKE_BUILD_TYPE_LOWER MATCHES "(release|relwithdebinfo|minsizerel)" AND (NOT ${CMAKE_C_FLAGS} MATCHES "FORTIFY_SOURCE=[3-9]"))

-            check_c_compiler_flag("-Wp,-D_FORTIFY_SOURCE=2" WITH_FORTIFY_SOURCE)

+            check_c_compiler_flag("-Wp,-D_FORTIFY_SOURCE=3" WITH_FORTIFY_SOURCE)

             if (WITH_FORTIFY_SOURCE)

-                set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wp,-D_FORTIFY_SOURCE=2")

+                set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wp,-D_FORTIFY_SOURCE=3")

             endif (WITH_FORTIFY_SOURCE)

         endif()

     endif()

--- a/src/CMakeLists.txt

+++ b/src/CMakeLists.txt

@@ -81,8 +81,8 @@ if(NOT MSVC)

   string(TOLOWER "${CMAKE_BUILD_TYPE}" CMAKE_BUILD_TYPE_LOWER)

   if(CMAKE_BUILD_TYPE_LOWER MATCHES "(release|relwithdebinfo|minsizerel)" AND ((NOT ${CMAKE_C_FLAGS} MATCHES "FORTIFY_SOURCE=[3-9]") AND (NOT ${CMAKE_CXX_FLAGS} MATCHES "FORTIFY_SOURCE=[3-9]")))

-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_FORTIFY_SOURCE=2")

-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D_FORTIFY_SOURCE=2")

+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_FORTIFY_SOURCE=3")

+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D_FORTIFY_SOURCE=3")

   endif()

   if (CMAKE_CXX_COMPILER MATCHES "Clang")