← Vulnerability feed

Vulnerability record · CVE-2021-20238 · published 1 April 2022

CVE-2021-20238: Redhat openshift container platform improper authentication vulnerability

Redhat · Openshift Container Platform

It was found in OpenShift Container Platform 4 that ignition config, served by the Machine Config Server, can be accessed externally from clusters without authentication. The MCS endpoint (port 22623) provides ignition configuration used for bootstrapping Nodes and can include some sensitive data, e.g. registry pull secrets. There are two scenarios where this data can be accessed. The first is on Baremetal, OpenStack, Ovirt, Vsphere and KubeVirt deployments which do not have a separate internal API endpoint and allow access from outside the cluster to port 22623 from the standard OpenShift API Virtual IP address. The second is on cloud deployments when using unsupported network plugins, which do not create iptables rules that prevent to port 22623. In this scenario, the ignition config is exposed to all pods within the cluster and cannot be accessed externally.

3.7 CVSS 3.1 Low EPSS 0.77% · top 46.2% CWE-287 · Improper authenticationCWE-306 · Missing authentication for critical function
3.7CVSS 3.1 base score, v2 4.3
0.77%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

It was found in OpenShift Container Platform 4 that ignition config, served by the Machine Config Server, can be accessed externally from clusters without authentication. The MCS endpoint (port 22623) provides ignition configuration used for bootstrapping Nodes and can include some sensitive data, e.g. registry pull secrets. There are two scenarios where this data can be accessed. The first is on Baremetal, OpenStack, Ovirt, Vsphere and KubeVirt deployments which do not have a separate internal API endpoint and allow access from outside the cluster to port 22623 from the standard OpenShift API Virtual IP address. The second is on cloud deployments when using unsupported network plugins, which do not create iptables rules that prevent to port 22623. In this scenario, the ignition config is exposed to all pods within the cluster and cannot be accessed externally.

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

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugzilla.redhat.com/show_bug.cgi?id=1926568 Issue TrackingMitigationVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1926568 Issue TrackingMitigationVendor Advisory

Track CVE-2021-20238 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2019-7609Kibana Timelion visualizer code injection enables remote code executionKibana before 5.6.15 and 6.6.1 contains an arbitrary code execution flaw in the Timelion visualizer. An attacker who can reach the Timelion applicati…KEVEPSS 95%analysed9.9CVE-2019-1003030Jenkins Pipeline Groovy Plugin sandbox bypass allows arbitrary code executionThe Jenkins Pipeline: Groovy Plugin (2.63 and earlier) contains a sandbox bypass in CpsGroovyShell.java. Attackers who can control pipeline scripts c…KEVEPSS 97%analysed9.9CVE-2019-1003029Jenkins Script Security Plugin sandbox bypass allows code executionThe Jenkins Script Security Plugin 1.53 and earlier fails to properly enforce its Groovy sandbox in GroovySandbox.java and SecureGroovyScript.java, l…KEVEPSS 74%analysed9.8CVE-2018-1000861Jenkins Stapler framework URL routing allows remote code executionThe Stapler web framework in Jenkins 2.153 and earlier and LTS 2.138.3 and earlier lets attackers invoke unintended Java methods by requesting crafte…KEVEPSS 98%analysed7.8CVE-2026-31431Linux kernel algif_aead in-place crypto operation flawThe Linux kernel's algif_aead AF_ALG AEAD interface operated in-place on buffers that come from different mappings, a flaw the fix resolves by revert…KEVEPSS 3.4%analysed7.8CVE-2021-3560polkit D-Bus credential check bypass allows local root escalationpolkit can be tricked into bypassing credential checks for D-Bus requests, letting an unprivileged local user elevate to root. Because polkit is a co…KEVEPSS 24%analysed7.8CVE-2019-0211Apache HTTP Server scoreboard use-after-free local privilege escalationApache HTTP Server 2.4.17 through 2.4.38 with MPM event, worker or prefork contains a use-after-free in scoreboard handling. Code running in a less-p…KEVEPSS 65%analysed7.5CVE-2023-44487HTTP/2 Rapid Reset stream cancellation denial of serviceThe HTTP/2 protocol permits a client to cancel many streams quickly, and the server's handling of those resets consumes disproportionate resources. T…KEVEPSS 100%analysed

Source: NIST National Vulnerability Database (record CVE-2021-20238), CISA KEV, FIRST EPSS (scores of 2026-10-01). This page is refreshed as NVD updates the record.