CVE-2026-73576

Weak JWT Signing Secret Generation Enables Token Forgery in Zimbra Collaboration

Published Aug 13, 2026 CVSS 3.1 · 6.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Synacor
Synacor zimbra Collaboration Suite
CPEs cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*
Vendors & Products Synacor
Synacor zimbra Collaboration Suite
Type Values Removed Values Added
Title Weak JWT Signing Secret Generation Enables Token Forgery in Zimbra Collaboration
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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Aug 13, 2026, 3:58 PM
Reserved
Aug 12, 2026, 10:03 PM
Status
Analyzed
Published
Aug 13, 2026, 4:19 PM
Modified
Aug 28, 2026, 1:08 PM