diff --git a/configure.ac b/configure.ac
index 0f809169fc0..72503f2b1ce 100644
--- a/configure.ac
+++ b/configure.ac
@@ -963,11 +963,11 @@ if test "$use_hardening" != "no"; then
   dnl However, FORTIFY_SOURCE requires that there is some level of optimization, otherwise it does nothing and just creates a compiler warning.
   dnl Since FORTIFY_SOURCE is a no-op without optimizations, do not enable it when enable_debug is yes.
   if test "$enable_debug" != "yes"; then
-    AX_CHECK_PREPROC_FLAG([-D_FORTIFY_SOURCE=2],[
+    AX_CHECK_PREPROC_FLAG([-D_FORTIFY_SOURCE=3],[
       AX_CHECK_PREPROC_FLAG([-U_FORTIFY_SOURCE],[
         HARDENED_CPPFLAGS="$HARDENED_CPPFLAGS -U_FORTIFY_SOURCE"
       ])
-      HARDENED_CPPFLAGS="$HARDENED_CPPFLAGS -D_FORTIFY_SOURCE=2"
+      HARDENED_CPPFLAGS="$HARDENED_CPPFLAGS -D_FORTIFY_SOURCE=3"
     ])
   fi