Unauthenticated administrator access via unsigned SAML session data
Published Jan 13, 2022 · Updated Oct 21, 2025
Authentication bypass in Zabbix Frontend 5.4.0 through 5.4.8 allows remote attackers to gain administrator access via SAML SSO. index_sso.php reads the client-controlled saml_data username attribute and calls loginByUsername without first invoking CEncryptedCookieSession::checkSign() or otherwise authenticating the stored attribute. SAML authentication must be enabled, and the attacker must know an existing Zabbix username; the default Admin account satisfies that condition, while the guest account is disabled by default.
Summary
What happened
Authentication bypass in Zabbix Frontend 5.4.0 through 5.4.8 allows remote attackers to gain administrator access via SAML SSO. index_sso.php reads the client-controlled saml_data username attribute and calls loginByUsername without first invoking CEncryptedCookieSession::checkSign() or otherwise authenticating the stored attribute. SAML authentication must be enabled, and the attacker must know an existing Zabbix username; the default Admin account satisfies that condition, while the guest account is disabled by default.
The record
- CVE
- CVE-2022-23131
- Published
- Jan 13, 2022
- Updated
- Oct 21, 2025
- Vendor
- Zabbix
- Product
- Zabbix Frontend
- Classifications
- CWE-290, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 13, 2022CVE publishedPublication date reported by the CVE source.
- Oct 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.4.0 - 5.4.8
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- SonarSource Zabbix SAML session-forgery demonstrationproof of concept · demonstrated
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Reported exploitation
- CISA Known Exploited Vulnerabilities catalog entryknown exploited catalog
Technologies
Your stack
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Your stack
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