diff --git a/crypto/fipsmodule/cipher/e_aes.c b/crypto/fipsmodule/cipher/e_aes.c
index ca55aa4..d349efb 100644
--- a/crypto/fipsmodule/cipher/e_aes.c
+++ b/crypto/fipsmodule/cipher/e_aes.c
@@ -68,6 +68,10 @@
 #endif
 
 
+#if !defined(UINT64_MAX)
+#define UINT64_MAX 18446744073709551615ULL
+#endif
+
 OPENSSL_MSVC_PRAGMA(warning(disable: 4702)) /* Unreachable code. */
 
 typedef struct {