Dear LibreSSL developers,

we identified a minor security issues in libressl-2.1.1.

Please confirm at your earliest convenience that you have received this vulnerability report. We will gladly work with you so you can successfully confirm and reproduce this issue.

Also note that this bug is NOT subject to a 90 day disclosure deadline. This is because exploitability is unlikely.

In the case you chose not to fix these issues please provide data points as we may make public all this information. In that case, we understand you will have no problem having this information public.

Once you have reproduced the issue, we’d appreciate to learn your expected timeline for a security update to be released. With any fix, please give credit for identifying the vulnerability to "Felix Groebert of the Google Security Team".

Don’t hesitate to let us know if you have any questions!

LibreSSL is vulnerable to CVE-2014-3510. From the CVE:

The ssl3_send_client_key_exchange function in s3_clnt.c in OpenSSL 0.9.8 before 0.9.8zb, 1.0.0 before 1.0.0n, and 1.0.1 before 1.0.1i allows remote DTLS servers to cause a denial of service (NULL pointer dereference and client application crash) via a crafted handshake message in conjunction with a (1) anonymous DH or (2) anonymous ECDH ciphersuite.

https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff;f=ssl/s3_clnt.c;h=0a006a75342893fd4f2fdd30f930ec220b7694fa;hp=9a94de00d8492a292995a90b3f0c45b1fe85e087;hb=17160033765480453be0a41335fa6b833691c049;hpb=280b1f1ad12131defcd986676a8fc9717aaa601b

Using specific anonymous cipher suites will result in a null pointer dereference in d1_clnt.c on line 988 and 1072 in function dtls1_send_client_key_exchange.

988                             if (s->session->sess_cert->peer_dh_tmp != NULL)

(gdb) p s->session->sess_cert
$1 = (struct sess_cert_st *) 0x0

We recommend to check if sess_cert is non NULL.

Cheers
Felix