diff --git a/src/libstrongswan/utils/utils.h b/src/libstrongswan/utils/utils.h
index 33b8d1956..ec994bfc5 100644
--- a/src/libstrongswan/utils/utils.h
+++ b/src/libstrongswan/utils/utils.h
@@ -25,6 +25,7 @@
 #define _GNU_SOURCE
 #include <sys/types.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include <stddef.h>
 #include <sys/time.h>
 #include <string.h>