diff --git a/src/kntlm/des.cpp b/src/kntlm/des.cpp
index 18d85bf..cfa5044 100644
--- a/src/kntlm/des.cpp
+++ b/src/kntlm/des.cpp
@@ -27,6 +27,7 @@
#include "des.h"
#include <string.h>
+#include <limits>
#include <qendian.h>
static void permute_ip(unsigned char *inblock, DES_KEY *key, unsigned char *outblock);