Zimbra's sudo configuration permits the zimbra user to execute the zmslapd binary as root with arbitrary parameters. As part of its intended functionality, zmslapd can load a user-defined configuration file, which includes plugins in the form of .so files, which also execute as root.
https://github.com/rapid7/metasploit-framework/pull/16807
https://darrenmartyn.ie/2021/10/27/zimbra-zmslapd-local-root-exploit/
https://attackerkb.com/topics/92AeLOE1M1/cve-2022-37393/rapid7-analysis