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.
Affected products
synacor: zimbra collaboration suite
References2
- wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy Vendor Advisory
- wiki.zimbra.com/wiki/Zimbra_Security_Advisories Vendor Advisory
Metrics
- CVSS 3.1
-
6.5
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - EPSS — exploit probability
- 0% percentile: 27 · as of 12 November 2026
- CWE
- CWE-1241
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.