Due to an issue with incorrect sudo permissions, Zimbra Collaboration Suite (ZCS) suffers from a local privilege escalation issue in versions 9.0.0 and prior, where the 'zimbra' user can effectively coerce postfix into running arbitrary commands as 'root'.

Zimbra before 8.8.15 Patch 10 and 9.x before 9.0.0 Patch 3 allows remote code execution via an avatar file. There is potential abuse of /service/upload servlet in the webmail subsystem. A user can upload executable files (exe,sh,bat,jar) in the Contact section of the mailbox as an avatar image for a contact. A user will receive a "Corrupt File" error, but the file is still uploaded and stored locally in /opt/zimbra/data/tmp/upload/, leaving it open to possible remote execution.