CVE-2021-22138

Monitoring data disclosure via improper certificate validation

Published May 13, 2021 · Updated Aug 3, 2024

Improper certificate validation in Logstash after 6.4.0 and before 6.8.15 or 7.12.0 allows man-in-the-middle attackers to read monitoring data. When a monitoring CA is configured, the monitoring client fails to verify the certificate returned by the configured monitoring server. An attacker must control the network path after an operator configures a trusted monitoring CA; the impact is limited to monitoring-data disclosure.

CVSS severity2.6
Low
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in Logstash after 6.4.0 and before 6.8.15 or 7.12.0 allows man-in-the-middle attackers to read monitoring data. When a monitoring CA is configured, the monitoring client fails to verify the certificate returned by the configured monitoring server. An attacker must control the network path after an operator configures a trusted monitoring CA; the impact is limited to monitoring-data disclosure.

The record

CVE
CVE-2021-22138
Published
May 13, 2021
Updated
Aug 3, 2024
Vendor
Elastic
Product
Elasticsearch
Classifications
CWE-295, T1557
Attack vector
adjacent
Privileges
unauthenticated

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=after 6.4.0 and before 6.8.15 and 7.12.0

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Elastic · Elasticsearchversion=after 6.4.0 and before 6.8.15 and 7.12.0

Published CVSS scores

2.6ElasticCVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
4.3NVDAV:N/AC:M/Au:N/C:P/I:N/A:N
3.7NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-295Improper Certificate Validation
T1557Adversary-in-the-Middle

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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