CVE-2021-20198Network attack vector

Unauthenticated container command execution via anonymous kubelet

Published Feb 23, 2021 · Updated Aug 3, 2024

Missing authentication in Red Hat OpenShift Installer before 0.9.0-master.0.20210125200451-95101da940b0 allows remote attackers to execute commands. Bootstrap manifests enable anonymous authentication on kubelet port 10250, so an unauthenticated /exec request runs arbitrary commands in active containers. Exposure is limited to reachable bootstrap nodes during installation; common IPI cloud deployments block the port, while UPI nodes can persist.

CVSS severity8.1
High
EPSS probability1.83%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authentication in Red Hat OpenShift Installer before 0.9.0-master.0.20210125200451-95101da940b0 allows remote attackers to execute commands. Bootstrap manifests enable anonymous authentication on kubelet port 10250, so an unauthenticated /exec request runs arbitrary commands in active containers. Exposure is limited to reachable bootstrap nodes during installation; common IPI cloud deployments block the port, while UPI nodes can persist.

The record

CVE
CVE-2021-20198
Published
Feb 23, 2021
Updated
Aug 3, 2024
Vendor
Red Hat
Product
OpenShift Installer
Classifications
CWE-306, T1059
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 23, 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=openshift/installer v0.9.0-master.0.20210125200451-95101da940b0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · OpenShift Installerversion=openshift/installer v0.9.0-master.0.20210125200451-95101da940b0

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
T1059Command and Scripting Interpreter

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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