CVE 2016-2112
The bundled LDAP client library in Samba 3.x and 4.x before 4.2.11, 4.3.x before 4.3.8, and 4.4.x before 4.4.2 does not recognize the "client ldap sasl wrapping" setting, which allows man-in-the-middle attackers to perform LDAP protocol-downgrade attacks by modifying the client-server data stream.
See the 
CVE page on Mitre.org
for more details.
