---
title: "CVE-2026-93639: Zimbra Collaboration Suite - Broken Access Control & Stored XSS"
description: "Zimbra Collaboration Suite (ZCS) 10.1.16 and 10.1.20 contain a broken access control caused by missing authorization in ConfigureZimletRequest, letting delegated administrators overwrite global Zimlet configuration and execute attacker-controlled scripts via crafted proxy URLs, exploit requires delegated-administrator account and victim interaction."
url: https://panop.io/threat-heartbeat/CVE-2026-93639/
---

# CVE-2026-93639 Zimbra Collaboration Suite - Broken Access Control & Stored XSS

Zimbra Collaboration Suite (ZCS) 10.1.16 and 10.1.20 contain a broken access control caused by missing authorization in ConfigureZimletRequest, letting delegated administrators overwrite global Zimlet configuration and execute attacker-controlled scripts via crafted proxy URLs, exploit requires delegated-administrator account and victim interaction.

CVSS base score 8.7 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.36% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-93639)

## Details

Type

Broken Access Control

Impact

Stored XSS, Broken Access Control, Information Disclosure

CVSS vector

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

Published

23 October 2026

Updated

25 October 2026

Weakness

[CWE-862](https://cwe.mitre.org/data/definitions/862.html)

## Vendor fix

Update to a version later than 10.1.20 or latest available version.

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-2026-93639](https://nvd.nist.gov/vuln/detail/CVE-2026-93639)
- [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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