CVE-2026-23934

Authenticated DoS via validate.api.exists

Published Aug 18, 2026 · Updated Aug 18, 2026

Denial of service in Zabbix 7.4.0 through 7.4.11 allows remote authenticated users to spike frontend CPU via validate.api.exists requests. Published detail is limited to crafted HTTP requests to the frontend validate.api.exists action; Zabbix has not disclosed the internal routine that performs the excessive work. An authenticated frontend account and reachability to the web UI are required, and the reported impact is bounded to disproportionate CPU load on the frontend web server rather than code execution or data access.

CVSS severity5.1
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Zabbix 7.4.0 through 7.4.11 allows remote authenticated users to spike frontend CPU via validate.api.exists requests. Published detail is limited to crafted HTTP requests to the frontend validate.api.exists action; Zabbix has not disclosed the internal routine that performs the excessive work. An authenticated frontend account and reachability to the web UI are required, and the reported impact is bounded to disproportionate CPU load on the frontend web server rather than code execution or data access.

The record

CVE
CVE-2026-23934
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Zabbix
Product
Zabbix
Classifications
CWE-405, T1499.003
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 2026Record 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=7.4.0 <=7.4.11 changes=[{"at":"7.4.12","status":"unaffected"}]

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

Zabbix · Zabbixversion=7.4.0 <=7.4.11 changes=[{"at":"7.4.12","status":"unaffected"}]

Published CVSS scores

5.1ZabbixCVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-405Asymmetric Resource Consumption (Amplification)
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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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