untrusted comment: signature from openbsd 6.0 base secret key
RWSho3oKSqgLQ+nvjojNv0BETtBpdOsfAjnPnz8Ko3XL5UcaGDRRrkHt9GulGnU/URXBZxe3q32aOgGIe01P3mF9iSo0umkskAQ=

OpenBSD 6.0 errata 13, Oct 10, 2016:

A protocol parsing bug in sshd can lead to unauthenticated memory
and CPU consumption.

Apply by doing:
    signify -Vep /etc/signify/openbsd-60-base.pub -x 013_ssh_kexinit.patch.sig \
        -m - | (cd /usr/src && patch -p0)

And then rebuild and install sshd:
    cd /usr/src/usr.bin/ssh
    make obj
    make depend
    make
    make install

Index: usr.bin/ssh/kex.c
===================================================================
RCS file: /cvs/src/usr.bin/ssh/kex.c,v
retrieving revision 1.118
retrieving revision 1.118.4.1
diff -p -u -IOpenBSD -r1.118 -r1.118.4.1
--- usr.bin/ssh/kex.c	2 May 2016 10:26:04 -0000	1.118
+++ usr.bin/ssh/kex.c	10 Oct 2016 19:35:47 -0000	1.118.4.1
@@ -452,6 +452,7 @@ kex_input_kexinit(int type, u_int32_t se
 	if (kex == NULL)
 		return SSH_ERR_INVALID_ARGUMENT;
 
+	ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, NULL);
 	ptr = sshpkt_ptr(ssh, &dlen);
 	if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)
 		return r;