diff --git a/client/cmdhf14a.c b/client/cmdhf14a.c
index ebf0ea4ac..61d337d47 100644
--- a/client/cmdhf14a.c
+++ b/client/cmdhf14a.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include "iso14443crc.h"
 #include "data.h"
diff --git a/client/cmdlf.c b/client/cmdlf.c
index 40bb8a215..97cd2c93a 100644
--- a/client/cmdlf.c
+++ b/client/cmdlf.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include "proxusb.h"
 #include "data.h"
diff --git a/client/cmdlfti.c b/client/cmdlfti.c
index a0e2bb842..dcb30746c 100644
--- a/client/cmdlfti.c
+++ b/client/cmdlfti.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdlib.h>
 #include "crc16.h"
 #include "proxusb.h"
 #include "data.h"
diff --git a/client/proxmark3.c b/client/proxmark3.c
index 830a12456..77c377158 100644
--- a/client/proxmark3.c
+++ b/client/proxmark3.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <pthread.h>
 #include <readline/readline.h>