RHSA-2026:40779: Important: OpenShift Container Platform 4.21.25 bug fix and security update

Published Jul 21, 2026
·
Updated

Important: OpenShift Container Platform 4.21.25 bug fix and security update

Other sources

Red Hat OpenShift Container Platform is Red Hat's cloud computing Kubernetes application platform solution designed for on-premise or private cloud deployments.This advisory contains the container images for Red Hat OpenShift Container Platform 4.21.25. See the following advisory for the RPM packages for this release:https://access.redhat.com/errata/RHBA-2026:40778 Space precludes documenting all of the container images in this advisory. See the following Release Notes documentation, which will be updated shortly for this release, for details about these changes:https://docs.redhat.com/en/documentation/openshiftcontainerplatform/4.21/html/releasenotes/ Security Fix(es): kernel: eventpoll: fix epremove struct eventpoll / struct file UAF (CVE-2026-46242) kernel: KVM: arm64: vgic-its: Drop the translation cache reference only for the erased entry (CVE-2026-46316) kernel: KVM: x86: Fix shadow paging use-after-free due to unexpected role (CVE-2026-53359) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.All OpenShift Container Platform 4.21 users are advised to upgrade to these updated packages and images when they are available in the appropriate release channel. To check for available updates, use the OpenShift CLI (oc) or web console. Instructions for upgrading a cluster are available at https://docs.redhat.com/en/documentation/openshiftcontainerplatform/4.21/html-single/updatingclusters/index#updating-cluster-cli.

Red Hat

Affected Software

4 affected components
Red Hat Red Hat OpenShift Container Platform for ARM 64
Red Hat Red Hat OpenShift Container Platform
Red Hat Red Hat OpenShift Container Platform for Power
Red Hat Red Hat OpenShift Container Platform for IBM Z and LinuxONE

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 4.21.25Patch RHBA-2026:40778

Event History

Jul 21, 2026
Advisory Published
via Red Hat·12:00 AM
Data Sourced
via Red Hat·12:00 AM
RemedyDescriptionAffected Software
Advisory Published
via Red Hat·03:06 PM
Data Sourced
via Red Hat·03:06 PM
Severity
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Frequently Asked Questions

1

What is the severity of RHSA-2026:40779?

The severity of RHSA-2026:40779 is classified as high with a score of 7.

2

How do I fix RHSA-2026:40779?

To fix RHSA-2026:40779, users should update their OpenShift Container Platform to version 4.21.25.

3

What vulnerabilities are addressed in RHSA-2026:40779?

RHSA-2026:40779 addresses a bug fix related to a Use After Free security vulnerability.

4

What systems are affected by RHSA-2026:40779?

RHSA-2026:40779 affects the Red Hat OpenShift Container Platform for ARM 64, Power, IBM Z, and LinuxONE.

5

When was RHSA-2026:40779 published?

RHSA-2026:40779 was published on July 21, 2026.

Contact

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