HrAddFBBlock in libfreebusy/freebusyutil.cpp in Kopano Groupware Core before 8.7.7 allows out-of-bounds access, as demonstrated by mishandling of an array copy during parsing of ICal data.
https://stash.kopano.io/projects/KC/repos/kopanocore/commits/4e02b420fff
https://stash.kopano.io/projects/KC/repos/kopanocore/browse/RELNOTES.txt
https://lists.debian.org/debian-lts-announce/2023/03/msg00006.html