diff --git a/common.mk b/common.mk
index 5894f1d..524243e 100644
--- a/common.mk
+++ b/common.mk
@@ -321,7 +321,7 @@
 COMMON_CFLAGS := -Wall -Werror -fno-strict-aliasing $(SSP_CFLAGS) -O1 -Wformat=2
 CXXFLAGS += $(COMMON_CFLAGS) $(COMMON_CFLAGS-$(CXXDRIVER)) -std=gnu++11
 CFLAGS += $(COMMON_CFLAGS) $(COMMON_CFLAGS-$(CDRIVER)) -std=gnu11
-CPPFLAGS += -D_FORTIFY_SOURCE=2
+CPPFLAGS += -D_FORTIFY_SOURCE=3
 
 # Enable large file support.
 CPPFLAGS += -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE