In Samba 4.1.0 to 4.6.7, a man in the middle attack can read and may alter confidential documents transferred via a client connection, which are reached via DFS redirect when the original connection used SMB3. https://www.samba.org/samba/security/CVE-2017-12151.html https://nvd.nist.gov/vuln/detail/CVE-2017-12151