---
id: CVE-2026-73576
title: "In Zimbra Collaboration (ZCS) before 10.1.17,\_weak cryptographic key generation vulnerability exists in the OnlyOffice integration"
summary: "In Zimbra Collaboration (ZCS) before 10.1.17,\_weak cryptographic key generation vulnerability exists in the OnlyOffice integration. The zimbraDocumentEditingJwtSecret is generated using an insecure random number generator, resulting in i…"
severity: medium
cvss: 6.3
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N'
cwe:
  - CWE-1241
published: '2026-08-13'
updated: '2026-08-21'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73576'
references:
  - url: 'https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy'
    label: cve@mitre.org
  - url: 'https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories'
    label: cve@mitre.org
tags:
  - nvd
epss: 0.00194
epssPercentile: 0.09369
ingestedAt: '2026-08-22T13:32:36.305Z'
---

## Overview

In Zimbra Collaboration (ZCS) before 10.1.17, weak cryptographic key generation vulnerability exists in the OnlyOffice integration. The zimbraDocumentEditingJwtSecret is generated using an insecure random number generator, resulting in insufficient entropy. An attacker who obtains a JWT signed with the generated secret may be able to recover the JWT signing secret through offline brute-force, potentially enabling JWT forgery.

## Remediation

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