RHSA-2026:51025 - Security Advisory

Topic

Red Hat OpenShift Container Platform release 4.21.28 is now available with updates to packages and images that fix several bugs and add enhancements.

This release includes a security update for Red Hat OpenShift Container Platform 4.21.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

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 4.21.28. See the following advisory for the RPM packages for this release:

https://access.redhat.com/errata/RHBA-2026:51020

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/openshift_container_platform/4.21/html/release_notes/

Solution

For OpenShift Container Platform 4.21 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html/release_notes/

You may download the oc tool and use it to inspect release image metadata for x86_64, s390x, ppc64le, and aarch64 architectures. The image digests may be found at https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags.

The sha values for the release are as follows:

(For x86_64 architecture)
The image digest is sha256:bc40cdbff48373c2b65a0b9805d7f98b1ce91589df5361f6fd2a94cf3d055cb3

(For s390x architecture)
The image digest is sha256:0bdf5d38e390951689501ad6636aa75627de3ec45ea026ac0b88dd1d94ec4963

(For ppc64le architecture)
The image digest is sha256:eadcb46628e5c09e121252651e5211173887fd61aff692bcbad22d7dff2f746f

(For aarch64 architecture)
The image digest is sha256:93fdc58c5d6fb401349c37de4b08292de7204a1c970398d7dc4bd0013d7f5cd1

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/openshift_container_platform/4.21/html-single/updating_clusters/index#updating-cluster-cli.

Affected Products

• Red Hat OpenShift Container Platform

Fixes

• BZ - 2483253
• OCPBUGS-100194 - set correct --advertise-client-url for etcd grpc-proxy
• OCPBUGS-100311 - Update Konflux release version
• OCPBUGS-100352 - [release-4.21] Alertmanager unit tests fail on release-4.21 (and earlier) due to expired certificates
• OCPBUGS-100377 - [release-4.21] Re-enable Knative Cypress e2e tests
• OCPBUGS-100390 - etcd 2x-3x memory usage regression between etcd 3.5 and 3.6 - scales with cluster size
• OCPBUGS-101761 - Update OVE UI Konflux references
• OCPBUGS-99453 - Gateway Pod can not pull wasm plugin behind an enterprise proxy
• OCPBUGS-99747 - frr-k8s pods enter permanent CrashLoopBackOff at scale due to startup probe timeout with large FRRConfiguration count (~4000 CRs / 1500 VRFs)

CVEs

• CVE-2026-49332

References

• https://access.redhat.com/security/updates/classification/