diff --git a/kexgexc.c b/kexgexc.c
index 3f20491..71ff133 100644
--- a/kexgexc.c
+++ b/kexgexc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexgexc.c,v 1.21 2015/04/13 02:04:08 djm Exp $ */
+/* $OpenBSD: kexgexc.c,v 1.22 2015/05/26 23:23:40 dtucker Exp $ */
 /*
  * Copyright (c) 2000 Niels Provos.  All rights reserved.
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
@@ -28,6 +28,7 @@
 
 #ifdef WITH_OPENSSL
 
+#include <sys/param.h>
 #include <sys/types.h>
 
 #include <openssl/dh.h>
@@ -65,6 +66,8 @@
 	kex->min = DH_GRP_MIN;
 	kex->max = DH_GRP_MAX;
 	kex->nbits = nbits;
+	if (datafellows & SSH_BUG_DHGEX_LARGE)
+		kex->nbits = MIN(kex->nbits, 4096);
 	/* New GEX request */
 	if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST)) != 0 ||
 	    (r = sshpkt_put_u32(ssh, kex->min)) != 0 ||