[openssl-users] OpenSSL 1.1.0 assertion failure: ssl_free_wbio_buffer()

Matt Caswell matt at openssl.org
Mon Apr 16 10:38:34 UTC 2018

On 16/04/18 09:19, Marcus.Schafheutle at gmx.de wrote:
> SSL_set_bio(ssl, NULL, NULL); // free BIOs when finished

There should be no reason to do this. The BIO's will get freed
automatically by the SSL_free() call.

> Is this a faulty behavior of OpenSSL 1.1.0 or is the fault on my side? 

This looks like a bug in OpenSSL. It should be able to tolerate passing
NULL for wbio in the SSL_set_bio call, but apparently it can't in the
case of a failed handshake. Please could you open an issue on github for

The workaround is to remove the SSL_set_bio(SSL, NULL, NULL) call. It
should not be necessary.


More information about the openssl-users mailing list