CVE-2022-23131Known exploitationPublic exploitNetwork attack vector

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.

CVSS severity9.8
Critical
EPSS probability95.68%
Next 30 days · Nov 1, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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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

  1. Jan 13, 2022CVE publishedPublication date reported by the CVE source.
  2. 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.

  1. Affected versionversion=5.4.0 - 5.4.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zabbix · Zabbix Frontendversion=5.4.0 - 5.4.8

Published CVSS scores

9.1ZabbixCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
5.1NIST NVDAV:N/AC:H/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsShadowserver observations through Sep 28, 2026. Gaps indicate unavailable data.
Sep 22, 2026Sep 28, 2026
View daily counts
Reporting dayUnique IPs
Sep 22, 20261
Sep 23, 2026Unavailable
Sep 24, 2026Unavailable
Sep 25, 20261
Sep 26, 20261
Sep 27, 20262
Sep 28, 20261
Latest reporting daySep 28, 2026
Latest daily unique IPs1
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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