1 files changed, 3 insertions, 2 deletions

diff --git a/sshkey-xmss.c b/sshkey-xmss.c
index a29e33f39..9e5f5e475 100644
--- a/sshkey-xmss.c
+++ b/sshkey-xmss.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey-xmss.c,v 1.5 2019/06/28 13:35:04 deraadt Exp $ */
+/* $OpenBSD: sshkey-xmss.c,v 1.6 2019/10/09 00:02:57 djm Exp $ */
 /*
  * Copyright (c) 2017 Markus Friedl.  All rights reserved.
  *
@@ -977,7 +977,8 @@ sshkey_xmss_decrypt_state(const struct sshkey *k, struct sshbuf *encoded,
                 goto out;
         }
         /* check that an appropriate amount of auth data is present */
-        if (sshbuf_len(encoded) < encrypted_len + authlen) {
+        if (sshbuf_len(encoded) < authlen ||
+            sshbuf_len(encoded) - authlen < encrypted_len) {
                 r = SSH_ERR_INVALID_FORMAT;
                 goto out;
         }