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: 6.9 [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]
CVE-ID: N/A
CWE-ID: CWE-338
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
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.
Affected software
Zimbra Collaboration
Remediation
Install security update from vendor's website.
Zimbra Collaboration - update to 10.1.17