CVE-2026-73576: Synacor Zimbra Collaboration Suite

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

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: before 10.1.17 (fixed in 10.1.17)

Published 2026-08-13. Last modified 2026-08-28.