---
id: CVE-2026-93640
title: >-
  Zimbra Collaboration Suite Local Privilege Escalation via Unrestricted
  zmunbound Sudo Configuration
summary: >-
  A local privilege escalation vulnerability in the optional dnscache package of
  Zimbra Collaboration Suite (ZCS) allows the Unix zimbra account to access
  files with root privileges. The passwordless sudo policy permits arbitrary
  arguments…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-732
vendor: Zimbra
product: Zimbra Collaboration Suite
affected:
  - collaboration_suite <= 10.1.21
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-23T13:48:27.697993Z'
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T13:50:34.330Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-93640'
references:
  - url: 'https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories'
  - url: >-
      https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/
tags:
  - cve.org
ingestedAt: '2026-10-23T14:28:08.699Z'
---

## Overview

A local privilege escalation vulnerability in the optional dnscache package of Zimbra Collaboration Suite (ZCS) allows the Unix zimbra account to access files with root privileges. The passwordless sudo policy permits arbitrary arguments to zmunbound, whose wrapper forwards them to Unbound without restricting the configuration path. An attacker can supply a configuration that retains root privileges and disables the chroot. Include directives expose root-readable file contents through parser errors, while an attacker-selected logfile path creates a root-owned file or appends Unbound log records to an existing file. This can disclose password hashes and private keys and corrupt privileged configuration files, preventing affected services from starting with the modified configuration. The affected configuration is present in ZCS 10.1.16 and 10.1.21 dnscache packages.

## Affected

- `collaboration_suite <= 10.1.21`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.