diff --git a/auth2-chall.c b/auth2-chall.c
index 98f3093..031c282 100644
--- a/auth2-chall.c
+++ b/auth2-chall.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-chall.c,v 1.38 2013/05/17 00:13:13 djm Exp $ */
+/* $OpenBSD: auth2-chall.c,v 1.39 2013/11/08 00:39:14 djm Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2001 Per Allansson.  All rights reserved.
@@ -111,7 +111,7 @@
 		remove_kbdint_device("pam");
 #endif
 
-	kbdintctxt = xmalloc(sizeof(KbdintAuthctxt));
+	kbdintctxt = xcalloc(1, sizeof(KbdintAuthctxt));
 	if (strcmp(devs, "") == 0) {
 		buffer_init(&b);
 		for (i = 0; devices[i]; i++) {