diff --git a/configure.ac b/configure.ac
index b5e04b168..0d88bff66 100644
--- a/configure.ac
+++ b/configure.ac
@@ -412,6 +412,8 @@ if test x$use_glibc_compat != xno; then
 fi
 
 if test x$use_hardening != xno; then
+  AX_CHECK_COMPILE_FLAG([-Wformat],[HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -Wformat"],[AC_MSG_ERROR(Cannot enable -Wformat)])
+  AX_CHECK_COMPILE_FLAG([-Wformat-security],[HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -Wformat-security"],[AC_MSG_ERROR(Cannot enable -Wformat-security)])
   AX_CHECK_COMPILE_FLAG([-Wstack-protector],[HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -Wstack-protector"],[AC_MSG_ERROR(Cannot enable -Wstack-protector)])
   AX_CHECK_COMPILE_FLAG([-fstack-protector-all],[HARDENED_CXXFLAGS="$HARDENED_CXXFLAGS -fstack-protector-all"],[AC_MSG_ERROR(Cannot enable -fstack-protector-all)])