CVE-2021-20238Network attack vector

Unauthenticated ignition configuration disclosure via exposed MCS endpoint

Published Apr 1, 2022 · Updated Aug 3, 2024

Authentication bypass in Red Hat OpenShift Machine Config Operator 4.9.0 and earlier allows remote attackers to read ignition configuration. The Machine Config Server returns the /config/worker bootstrap document on port 22623 without authentication, while access control depends on network-plugin iptables filtering. External exposure occurs on deployments lacking a separate internal API endpoint; unsupported cloud network plugins instead expose the data to pods, including possible registry pull secrets.

CVSS severity3.7
Low
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Red Hat OpenShift Machine Config Operator 4.9.0 and earlier allows remote attackers to read ignition configuration. The Machine Config Server returns the /config/worker bootstrap document on port 22623 without authentication, while access control depends on network-plugin iptables filtering. External exposure occurs on deployments lacking a separate internal API endpoint; unsupported cloud network plugins instead expose the data to pods, including possible registry pull secrets.

The record

CVE
CVE-2021-20238
Published
Apr 1, 2022
Updated
Aug 3, 2024
Vendor
Red Hat
Product
OpenShift Machine Config Operator
Classifications
CWE-287, CWE-306, T1552.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 2022CVE 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=affecting versions up to, including ose-machine-config-operator-container-v4.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · OpenShift Machine Config Operatorversion=affecting versions up to, including ose-machine-config-operator-container-v4.9.0

Published CVSS scores

3.7NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:P/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
CWE-306Missing Authentication for Critical Function
T1552.001Credentials In Files

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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