Local Privilege Escalation in Zimbra Collaboration Suite by Zimbra

CVE-2026-50056

What is CVE-2026-50056?

A vulnerability exists in the Zimbra Collaboration Suite that allows the zimbra Unix account to execute arbitrary commands with root privileges. This issue arises from an insufficient restriction of JVM arguments in the passwordless sudo interface of the zmmailboxdmgr launcher. An attacker who has local command execution capabilities as the zimbra user can exploit this vulnerability by delaying Jetty's privilege drop and registering commands that trigger OnOutOfMemoryError. Consequently, when the server reaches heap exhaustion during startup, this command can execute while the Java Virtual Machine still operates with root access. Affected versions include ZCS 10.1.16 and 10.1.21, which are vulnerable to exploitation leading to security breaches.

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