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. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-2112