CVE-2021-27927: Zabbix

High severity, CVSS 8.8. EPSS: 2.2% chance of exploitation in the next 30 days.

In Zabbix from 4.0.x before 4.0.28rc1, 5.0.0alpha1 before 5.0.10rc1, 5.2.x before 5.2.6rc1, and 5.4.0alpha1 before 5.4.0beta2, the CControllerAuthenticationUpdate controller lacks a CSRF protection mechanism. The code inside this controller calls diableSIDValidation inside the init() method. An attacker doesn't have to know Zabbix user login credentials, but has to know the correct Zabbix URL and contact information of an existing user with sufficient privileges.

Affected products

• Zabbix Zabbix: from 4.0.0, up to and including 4.0.27; from 5.0.0, up to and including 5.0.9; from 5.2.0, up to and including 5.2.3

Published 2021-03-03. Last modified 2026-06-17.