---
title: "CVE-2026-93640: Zimbra Collaboration Suite - Privilege Escalation"
description: "Zimbra Collaboration Suite (ZCS) 10.1.16 and 10.1.21 dnscache packages contain a local privilege escalation caused by unrestricted arguments to zmunbound forwarding to Unbound, letting local attackers access root files and modify configurations, exploit requires local Unix zimbra account."
url: https://panop.io/threat-heartbeat/CVE-2026-93640/
---

# CVE-2026-93640 Zimbra Collaboration Suite - Privilege Escalation

Zimbra Collaboration Suite (ZCS) 10.1.16 and 10.1.21 dnscache packages contain a local privilege escalation caused by unrestricted arguments to zmunbound forwarding to Unbound, letting local attackers access root files and modify configurations, exploit requires local Unix zimbra account.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.14% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-93640)

## Details

Type

Privilege Escalation

Impact

Privilege Escalation, Information Disclosure, Data Tampering, Denial Of Service

CVSS vector

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

Published

23 October 2026

Updated

25 October 2026

Weakness

[CWE-732](https://cwe.mitre.org/data/definitions/732.html)

## Vendor fix

Update dnscache package to a version later than 10.1.21 or apply vendor patches.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-93640](https://nvd.nist.gov/vuln/detail/CVE-2026-93640)
- [https://wiki.zimbra.com/wiki/Zimbra\_Security\_Advisories](https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories)
- [https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/](https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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