An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0. An attacker can upload arbitrary files through amavis via a cpio loophole (extraction to /opt/zimbra/jetty/webapps/zimbra/public) that can lead to incorrect access to any other user accounts. Zimbra recommends pax over cpio. Also, pax is in the prerequisites of Zimbra on Ubuntu; however, pax is no longer part of a default Red Hat installation after RHEL 6 (or CentOS 6). Once pax is installed, amavis automatically prefers it over cpio.
https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-207a
https://www.tenable.com/cyber-exposure/tenable-2022-threat-landscape-report
https://www.secpod.com/blog/unpatched-rce-bug-in-zimbra-collaboration-suite-exploited-in-wild/
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
https://wiki.zimbra.com/wiki/Security_Center
https://forums.zimbra.org/viewtopic.php?t=71153&p=306532
http://packetstormsecurity.com/files/169458/Zimbra-Collaboration-Suite-TAR-Path-Traversal.html