Several vulnerabilities have been discovered in Samba, a SMB/CIFS file, print, and login server for Unix. CVE-2016-2124 Stefan Metzmacher reported that SMB1 client connections can be downgraded to plaintext authentication. CVE-2020-25717 Andrew Bartlett reported that Samba may map domain users to local users in an undesired way, allowing for privilege escalation. The update introduces a new parameter min domain uid to not accept a UNIX uid below this value. CVE-2020-25718 Andrew Bartlett reported that Samba as AD DC, when joined by an RODC, did not confirm if the RODC was allowed to print a ticket for that user, allowing an RODC to print administrator tickets. CVE-2020-25719 Andrew Bartlett reported that Samba as AD DC, did not always rely on the SID and PAC in Kerberos tickets and could be confused about the user a ticket represents. If a privileged account was attacked this could lead to total domain compromise. CVE-2020-25721 Andrew Bartlett reported that Samba as a AD DC did not provide a way for Linux applications to obtain a reliable SID in issued tickets. CVE-2020-25722 Andrew Bartlett reported that Samba as AD DC did not do sufficient access and conformance checking of data stored, potentially allowing total domain compromise. CVE-2021-3738 William Ross reported that the Samba AD DC RPC server can use memory that was free"d when a sub-connection is closed, resulting in denial of service, and potentially, escalation of privileges. CVE-2021-23192 Stefan Metzmacher reported that if a client to a Samba server sent a very large DCE/RPC request, and chose to fragment it, an attacker could replace later fragments with their own data, bypassing the signature requirements.