An issue in provider/libserver/ECKrbAuth.cpp of Kopano Core <= v11.0.2.51 contains an issue which allows attackers to authenticate even if the user account or password is expired. It also exists in the predecessor Zarafa Collaboration Platform (ZCP) in provider/libserver/ECPamAuth.cpp of Zarafa >= 6.30 (introduced between 6.30.0 RC1e and 6.30.8 final).
https://stash.kopano.io/projects/KC/repos/kopanocore/browse/provider/libserver/ECKrbAuth.cpp#137
https://src.fedoraproject.org/rpms/zarafa/c/a5a8366ccf07f248fae6edffb5123cfda579bfdb?branch=epel7
https://lists.debian.org/debian-lts-announce/2023/03/msg00006.html
https://jira.kopano.io/browse/KC-2021
https://github.com/Kopano-dev/kopano-core/blob/master/provider/libserver/ECKrbAuth.cpp#L137
https://bugzilla.redhat.com/show_bug.cgi?id=2192126
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2023-342b96903b