diff --git a/src/bignum.c b/src/bignum.c
index 6904c5d9..14b5aa54 100644
--- a/src/bignum.c
+++ b/src/bignum.c
@@ -19,6 +19,8 @@
  * MA 02111-1307, USA.
  */
 
+#include <stdio.h>
+
 #include "libssh/priv.h"
 #include "libssh/bignum.h"
 #include "libssh/string.h"