RHSA-2026:57457HighCVSS 8.1

Red Hat Security Advisory: OpenShift Container Platform 4.21.30 bug fix and security update

Published
August 25, 2026
Last Modified
September 17, 2026

🔗 CVE IDs covered (3)

CVE-2025-54518 →CVE-2026-43112 →CVE-2026-46483 →

📋 Description

CVE-2025-54518 — kernel: xen: AMD Zen 2 Processors: Privilege escalation via improper CPU cache isolation CVE-2026-43112 — kernel: fs/smb/client: fix out-of-bounds read in cifs_sanitize_prepath CVE-2026-46483 — vim: command injection when decompressing .tgz archives

🎯 Affected products5

  • Red Hat OpenShift Container Platform 4.21
  • rhcos-aarch64-4.21.9.6.202608180431-0 as a component of Red Hat OpenShift Container Platform 4.21
  • rhcos-ppc64le-4.21.9.6.202608180431-0 as a component of Red Hat OpenShift Container Platform 4.21
  • rhcos-s390x-4.21.9.6.202608180431-0 as a component of Red Hat OpenShift Container Platform 4.21
  • rhcos-x86_64-4.21.9.6.202608180431-0 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 sha256:249ceebaa2b02ce15ab132d36db4c0babffa8b783fcbb7e328bec5301742e904 (For s390x architecture) The image digest is sha256:9a4dbf0b6b633404ebd59da5a1d8d646f2693c0aae16ea9d69acf96b4e8494f9 (For ppc64le architecture) The image digest is sha256:bd47f591cf8e997beb46d29c5bbdec946ca96c44ad4fb87b904a1794d03627fa (For aarch64 architecture) The image digest is sha256:ffe299bf20746f9b40431e5edb66ddcfb77effe9389a966c8edb20388b10223a 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: To mitigate this issue, prevent the `cifs` kernel module from loading if CIFS client functionality is not required. This can be achieved by blacklisting the module. Create a file named `/etc/modprobe.d/blacklist-cifs.conf` with the following content: ``` blacklist cifs ``` After creating the file, regenerate the initramfs and reboot the system for the changes to take effect. ```bash dracut -f -v reboot ``` Disabling the `cifs` module will prevent the system from mounting CIFS network shares, which may impact functionality relying on this protocol. Workaround: To mitigate this vulnerability, do not decompress untrusted .tgz archives with the Vimuntar command. Use 'tar -x -z -f' directly, instead.

🔗 References (6)