CVE-2026-42400Network attack vector

Authenticated denial of service via compressed requests

Published May 28, 2026 · Updated May 28, 2026

Uncontrolled resource consumption in Elastic Kibana allows remote authenticated users to crash the service with a compressed request. The request-processing path expands attacker-controlled compressed payloads before authorization checks, allowing the decompressed size to consume excessive memory and CPU. Every configuration reachable by authenticated users is exposed, and successful requests can leave the Kibana instance unresponsive or terminate its process.

CVSS severity6.5
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in Elastic Kibana allows remote authenticated users to crash the service with a compressed request. The request-processing path expands attacker-controlled compressed payloads before authorization checks, allowing the decompressed size to consume excessive memory and CPU. Every configuration reachable by authenticated users is exposed, and successful requests can leave the Kibana instance unresponsive or terminate its process.

The record

CVE
CVE-2026-42400
Published
May 28, 2026
Updated
May 28, 2026
Vendor
Elastic
Product
Kibana
Classifications
CWE-400, CAPEC-130, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 28, 2026CVE publishedPublication date reported by the CVE source.
  2. May 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.0.0 <=8.19.15
  2. Affected versionversion=9.0.0 <=9.3.4
  3. Affected versionversion=9.4.0 <=9.4.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Elastic · Kibanaversion=8.0.0 <=8.19.15; version=9.0.0 <=9.3.4; version=9.4.0 <=9.4.1

Published CVSS scores

6.5ElasticCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CAPEC-130Excessive Allocation
T1499Endpoint Denial of Service

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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