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.

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required Low

Scope Changed

Confidentiality Impact None

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Zimbra Collaboration unaffected
Version Status Constraints
0 affected < 10.1.17

No data.

No data.

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Project Subscriptions

Vendors Products
Zimbra Subscribe
Collaboration Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy cve-icon cve-icon
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories cve-icon cve-icon
History

Thu, 13 Aug 2026 17:00:00 +0000

Type Values Removed Values Added
Title Weak JWT Signing Secret Generation Enables Token Forgery in Zimbra Collaboration

Thu, 13 Aug 2026 15:45:00 +0000

Type Values Removed Values Added
Description 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.
First Time appeared Zimbra
Zimbra collaboration
Weaknesses CWE-1241
CPEs cpe:2.3:a:zimbra:collaboration:*:*:*:*:*:*:*:*
Vendors & Products Zimbra
Zimbra collaboration
References
Metrics cvssV3_1

{'score': 6.3, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-08-13T15:58:52.960Z

Reserved: 2026-08-12T22:03:36.180Z

Link: CVE-2026-73576

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-13T16:19:06.923

Modified: 2026-08-13T16:19:06.923

Link: CVE-2026-73576

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-13T16:45:04Z

Weaknesses