From HEAD:

Fix flaw if 'Server Key exchange message' is omitted from a TLS
handshake which could lead to a cilent crash as found using the
Codenomicon TLS test suite (CVE-2008-1672)

Reviewed by: openssl-security@openssl.org

Obtained from: mark@awe.com

CHANGES

@@ -690,6 +690,11 @@
 
  Changes between 0.9.8g and 0.9.8h  [xx XXX xxxx]
 
+  *) Fix flaw if 'Server Key exchange message' is omitted from a TLS
+     handshake which could lead to a cilent crash as found using the
+     Codenomicon TLS test suite (CVE-2008-1672) 
+     [Steve Henson, Mark Cox]
+
   *) Fix double free in TLS server name extensions which could lead to
      a remote crash found by Codenomicon TLS test suite (CVE-2008-0891) 
      [Joe Orton]

ssl/s3_clnt.c

@@ -2143,6 +2143,13 @@ int ssl3_send_client_key_exchange(SSL *s)
 			{
 			DH *dh_srvr,*dh_clnt;
 
+			if (s->session->sess_cert == NULL) 
+				{
+				ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_UNEXPECTED_MESSAGE);
+				SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE,SSL_R_UNEXPECTED_MESSAGE);
+				goto err;
+				}
+
 			if (s->session->sess_cert->peer_dh_tmp != NULL)
 				dh_srvr=s->session->sess_cert->peer_dh_tmp;
 			else