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CVE-2021-20238

17
FAUCET Score

CVE-2021-20238 describes an authentication bypass vulnerability in OpenShift Container Platform 4, allowing external access to sensitive ignition configurations, including registry pull secrets, from the Machine Config Server (MCS) endpoint (port 22623). This affects Red Hat OpenShift Container Platform and OpenShift Machine Config Operator, particularly in baremetal, OpenStack, Ovirt, vSphere, and KubeVirt deployments, or cloud deployments using unsupported network plugins. The vulnerability has a CVSS score of 3.7 (LOW), indicating a network attack vector with high attack complexity and a potential for low confidentiality impact. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
4.0CPE matchmatch criteria
cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
<= 4.9.0CPE matchmatch criteria
cpe:2.3:a:redhat:openshift_machine-config-operator:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

3.7LOW

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.73%
Probability of exploitation in next 30 days
EPSS Percentile
50.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0073 is in the 32nd percentile among its peer group of 1,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.3 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (2)

redhatworkaround availablevia nvd_reference
View patch
redhatend of lifevia redhat_api
Product: Red Hat OpenShift Container Platform 4Fixed in: openshift4/ose-machine-config-rhel9-operator

Vendor Advisories (1)

redhatCVE-2021-20238Moderate

openshift/machine-config-operator: unauthenticated access to Machine Config Server ignition config

Feb 5, 2021

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingMitigationVendor Advisory