Debian-edu-config all versions < 2.11.10, a set of configuration files used for Debian Edu, and debian-lan-config < 0.26, configured too permissive ACLs for the Kerberos admin server, which allowed password changes for other Kerberos user principals.
https://www.debian.org/security/2019/dsa-4595
https://www.debian.org/security/2019/dsa-4589
https://usn.ubuntu.com/4530-1/
https://security-tracker.debian.org/tracker/CVE-2019-3467
https://seclists.org/bugtraq/2019/Dec/44
https://seclists.org/bugtraq/2019/Dec/34
https://lists.debian.org/debian-lts-announce/2020/01/msg00012.html
https://lists.debian.org/debian-lts-announce/2019/12/msg00023.html