CVE-2021-27927Public exploitNetwork attack vector

Administrator takeover via missing CSRF token validation

Published Mar 3, 2021 · Updated Aug 3, 2024

CSRF in Zabbix Frontend 4.0.x, 5.0.x, 5.2.x, and early 5.4 releases allows remote attackers to alter authentication settings via a crafted URL. CControllerAuthenticationUpdate disables SID validation and treats GET query parameters as form input without requiring an anti-CSRF token. Exploitation requires a privileged user to open the URL; redirecting authentication to an attacker-controlled LDAP server grants administrator access and, in some configurations, command execution on monitored hosts.

CVSS severity8.8
High
EPSS probability2.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSRF in Zabbix Frontend 4.0.x, 5.0.x, 5.2.x, and early 5.4 releases allows remote attackers to alter authentication settings via a crafted URL. CControllerAuthenticationUpdate disables SID validation and treats GET query parameters as form input without requiring an anti-CSRF token. Exploitation requires a privileged user to open the URL; redirecting authentication to an attacker-controlled LDAP server grants administrator access and, in some configurations, command execution on monitored hosts.

The record

CVE
CVE-2021-27927
Published
Mar 3, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-352, CAPEC-62, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)
CAPEC-62Cross Site Request Forgery
T1204.001User Execution: Malicious Link

Public exploit references

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

Technologies

Your stack

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Your stack

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