As per samba upstream advisory:
All versions of Samba prior to 4.16.x built with Heimdal Kerberos are vulnerable to an Elevation of Privilege attack. If the password of a user expires and need to be changed, a user could get a krbtgt using kpasswd with canonicalization turned on. The KDC should only provide a ticket for kadmin/changepw but returns a krbtgt. So a user could skip the password change and just use the krbtgt to get service tickets and use services in the forest.
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):