GnuTLS -- null pointer dereference

The GnuTLS project reports:

It was found by oss-fuzz that the server sending a
“no_renegotiation” alert in an unexpected timing, followed by an
invalid second handshake can cause a TLS 1.3 client to crash via a
null-pointer dereference. The crash happens in the application’s
error handling path, where the gnutls_deinit function is called
after detecting a handshake failure.