Published: 9 November 2021
A flaw was found in the way Samba, as an Active Directory Domain Controller, implemented Kerberos name-based authentication. The Samba AD DC, could become confused about the user a ticket represents if it did not strictly require a Kerberos PAC and always use the SIDs found within. The result could include total domain compromise.
CVSS 3 base score: 7.2
Launchpad, Ubuntu, Debian
Fixing this in Ubuntu 18.04 LTS would require substantial code backports. We will not be fixing this issue in Ubuntu 18.04 LTS. In environments where this is of concern, we recommend updating to a more recent Ubuntu version.