Zimbra Collaboration Suite Local Privilege Escalation via Unrestricted Postfix Sudo Permissions

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

A local privilege escalation vulnerability in the Zimbra Collaboration Suite (ZCS) MTA package allows the Unix zimbra account to execute arbitrary commands as root. The installed sudo policy permits passwordless root execution of Postfix administration commands without restricting their arguments. An attacker can select a zimbra-controlled daemon_directory in the Postfix configuration and invoke postfix set-permissions, causing Postfix to execute the attacker's post-install program as root. The Postfix configuration directory is also writable by zimbra, so restricting postconf alone does not remove the execution path. Exploitation requires local command execution as zimbra on an MTA node. ZCS 10.1.16 and 10.1.21 are affected.

Source published

23 Oct 2026 13:33:29 UTC

Source modified

24 Oct 2026 03:55:21 UTC

Observed here

24 Oct 2026 04:48:20 UTC

Source terms

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CVSS 3.1 · 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H