RHSA-2026:21695HighCVSS 8.2

Red Hat Security Advisory: OpenShift Container Platform 4.12.91 bug fix and security update

Published
June 4, 2026
Last Modified
August 21, 2026

🔗 CVE IDs covered (7)

CVE-2025-9714 →CVE-2026-3497 →CVE-2026-27135 →CVE-2026-35535 →CVE-2026-43284 →CVE-2026-43503 →CVE-2026-46300 →

📋 Description

CVE-2025-9714 — libxslt: libxml2: Inifinite recursion at exsltDynMapFunction function in libexslt/dynamic.c CVE-2026-3497 — openssh: OpenSSH GSSAPI: Information disclosure or denial of service due to uninitialized variables CVE-2026-27135 — nghttp2: nghttp2: Denial of Service via malformed HTTP/2 frames after session termination CVE-2026-35535 — sudo: Sudo: Privilege escalation due to failure in privilege drop calls CVE-2026-43284 — kernel: "Dirty Frag" ESP XFRM variant is a new universal Local Privilege Escalation (LPE) vulnerability in the Linux kernel CVE-2026-43503 — kernel: net: skbuff: propagate shared-frag marker through frag-transfer helpers CVE-2026-46300 — kernel: "Fragnesia" is a variant of Dirty Frag vulnerability in the ESP/XFRM leading to Local Privilege Escalation (LPE) vulnerability in the Linux kernel

🎯 Affected products2

  • Red Hat OpenShift Container Platform 4.12
  • rhcos-x86_64-412.86.202605271418-0 as a component of Red Hat OpenShift Container Platform 4.12

✅ Remediation

For OpenShift Container Platform 4.12 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/4.12/html/release_notes You may download the oc tool and use it to inspect release image metadata for x86_64 architecture. The image digest may be found at https://quay.io/repository/openshift-release-dev/ocp-release?tab=tags. The sha value for the release is as follows: (For x86_64 architecture) The image digest is sha256:3701cb0c9cd5c3123709a9ec33af15b4c6fe414f62b316a27cbbc07f5857a869 All OpenShift Container Platform 4.12 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/4.12/html-single/updating_clusters/index#updating-cluster-within-minor. Workaround: The impact of this flaw may be reduced by setting strict resource limits to the stack size of processes at the operational system level. This can be achieved either through the 'ulimit' shell built-in or the 'limits.conf' file. Workaround: To mitigate this issue, disable GSSAPI key exchange in the OpenSSH server configuration. This prevents the server from processing GSSAPI messages, eliminating the vulnerability's attack surface. Edit `/etc/ssh/sshd_config` and add or modify the line: ``` GSSAPIKeyExchange no ``` After saving the changes, restart the `sshd` service for the mitigation to take effect. This action will prevent users from authenticating via GSSAPI. ``` # systemctl restart sshd ``` Workaround: See the security bulletin for a detailed mitigation procedure.

🔗 References (9)