Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) in Zimbra Collaboration - #VU134811

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Main Vulnerability Database Vulnerabilities #VU134811

Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) in Zimbra Collaboration - #VU134811

Published: June 18, 2026


Vulnerability identifier: #VU134811
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-338
Exploitation vector: Remote access
Exploit availability: No public exploit available
Vendor: Synacor Inc.
Affected software:
Zimbra Collaboration

Detailed vulnerability description

The vulnerability allows a remote attacker to brute-force the JWT signing secret offline.

The vulnerability exists due to use of a weak pseudo-random number generator in zimbraDocumentEditingJwtSecret generation when creating the JWT signing secret. A remote attacker can perform offline guessing attacks to brute-force the JWT signing secret.


Remediation

Install security update from vendor's website.

Sources