CVE-2021-22139Network attack vector

Service outage via unbounded webhook responses

Published May 13, 2021 · Updated Aug 3, 2024

Denial of service in Elastic Kibana before 7.12.1 allows remote authenticated users to interrupt service through webhook actions. Webhook actions accept responses without a timeout or response-size limit, allowing requests to occupy and exhaust the Kibana host connection pool. Permission to create webhook actions is required; exhaustion makes Kibana unavailable to all other users.

CVSS severity4.9
Medium
EPSS probability1.00%
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 Elastic Kibana before 7.12.1 allows remote authenticated users to interrupt service through webhook actions. Webhook actions accept responses without a timeout or response-size limit, allowing requests to occupy and exhaust the Kibana host connection pool. Permission to create webhook actions is required; exhaustion makes Kibana unavailable to all other users.

The record

CVE
CVE-2021-22139
Published
May 13, 2021
Updated
Aug 3, 2024
Vendor
Elastic
Product
Kibana
Classifications
CWE-400, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 13, 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?

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

  1. Affected versionversion=before 7.12.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Elastic · Kibanaversion=before 7.12.1

Published CVSS scores

6.5NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.9ElasticCVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
4.0NVDAV:N/AC:L/Au:S/C:N/I:N/A:P

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.

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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
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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