samba is vulnerable to man-in-the-middle attack. A flaw was found in the way Samba initiated signed DCE/RPC connections. A man-in-the-middle attacker could use this flaw to downgrade the connection to not use signing and therefore impersonate the server.
lists.opensuse.org/opensuse-updates/2016-07/msg00060.html
rhn.redhat.com/errata/RHSA-2016-1486.html
rhn.redhat.com/errata/RHSA-2016-1487.html
rhn.redhat.com/errata/RHSA-2016-1494.html
www.oracle.com/technetwork/topics/security/linuxbulletinjul2016-3090544.html
www.securityfocus.com/bid/91700
www.securitytracker.com/id/1036244
access.redhat.com/security/updates/classification/#moderate
rhn.redhat.com/errata/RHSA-2016-1494.html
security.gentoo.org/glsa/201805-07
www.samba.org/samba/security/CVE-2016-2119.html