Agents are able to list appointments in the calendars without required permissions. This issue affects: OTRS AG ((OTRS)) Community Edition: 6.0.x version 6.0.1 and later versions. OTRS AG OTRS: 7.0.x versions prior to 7.0.27.
https://otrs.com/release-notes/otrs-security-advisory-2021-14/
https://lists.debian.org/debian-lts-announce/2023/08/msg00040.html