diff --git a/cmsis/TARGET_CORTEX_M/mbed_fault_handler.c b/cmsis/TARGET_CORTEX_M/mbed_fault_handler.c
index 62fa90ff07c..5c0f20b21ac 100644
--- a/cmsis/TARGET_CORTEX_M/mbed_fault_handler.c
+++ b/cmsis/TARGET_CORTEX_M/mbed_fault_handler.c
@@ -18,6 +18,7 @@
 #define __STDC_FORMAT_MACROS
 #endif
 #include <inttypes.h>
+#include <string.h>
 
 #include "device.h"
 #include "mbed_error.h"