RHSA-2026:34764HighCVSS 7.8

Red Hat Security Advisory: OpenShift Container Platform 4.21.23 bug fix and security update

Published
July 7, 2026
Last Modified
August 21, 2026

🔗 CVE IDs covered (3)

CVE-2026-42009 →CVE-2026-42010 →CVE-2026-46243 →

📋 Description

CVE-2026-42009 — gnutls: gnutls: Denial of Service via DTLS packet reordering vulnerability CVE-2026-42010 — gnutls: gnutls: Authentication Bypass via NUL Character in Username CVE-2026-46243 — kernel: Linux kernel: smb: client: reject userspace cifs.spnego descriptions

🎯 Affected products5

  • Red Hat OpenShift Container Platform 4.21
  • rhcos-aarch64-4.21.9.6.202607011303-0 as a component of Red Hat OpenShift Container Platform 4.21
  • rhcos-ppc64le-4.21.9.6.202607011303-0 as a component of Red Hat OpenShift Container Platform 4.21
  • rhcos-s390x-4.21.9.6.202607011303-0 as a component of Red Hat OpenShift Container Platform 4.21
  • rhcos-x86_64-4.21.9.6.202607011303-0 as a component of Red Hat OpenShift Container Platform 4.21

✅ Remediation

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:c58d65eeaf399b6850e5cc637a199ed44066819ccbc25877a6afd44ff861d841 (For s390x architecture) The image digest is sha256:5c89334e4cf13c60df32762ea475b863c7eeb5bc2cc5dafbbf65fc5351f520c6 (For ppc64le architecture) The image digest is sha256:d723c3c1ca165d75bbef247f412664c36bee48ac9ce26cbddf37553c9bb736f1 (For aarch64 architecture) The image digest is sha256:588cfd15da44d83f3f6375545de8c3e08c4a10f02a6f591a4b5d2e8ffe427497 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. Workaround: See the security bulletin for a detailed mitigation procedure.

🔗 References (7)