RHSA-2026:9835MediumCVSS 7.8

Red Hat Security Advisory: kernel-rt security update

Published
April 22, 2026
Last Modified
September 11, 2026

🔗 CVE IDs covered (3)

CVE-2026-23231 →CVE-2026-23001 →CVE-2026-23204 →

📋 Description

CVE-2026-23001 — kernel: macvlan: fix possible UAF in macvlan_forward_source() CVE-2026-23204 — kernel: net/sched: cls_u32: use skb_header_pointer_careful() CVE-2026-23231 — kernel: kernel: Privilege escalation or denial of service via use-after-free in nf_tables_addchain()

🎯 Affected products32

  • Red Hat Enterprise Linux NFV E4S (v.9.0)
  • Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-0:5.14.0-70.175.1.rt21.247.el9_0.src as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-0:5.14.0-70.175.1.rt21.247.el9_0.src as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-core-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-core-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-debug-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-debug-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-debug-core-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-debug-core-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-debug-debuginfo-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-debug-debuginfo-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-debug-devel-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-debug-devel-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-debug-kvm-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-debug-modules-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-debug-modules-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-debug-modules-extra-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-debug-modules-extra-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-debuginfo-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-debuginfo-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-debuginfo-common-x86_64-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-debuginfo-common-x86_64-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-devel-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-devel-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • kernel-rt-kvm-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-modules-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux NFV E4S (v.9.0)
  • kernel-rt-modules-0:5.14.0-70.175.1.rt21.247.el9_0.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.0)
  • +2 more not shown

✅ Remediation

For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Workaround: To mitigate this issue, prevent module macvlan from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically. Workaround: In order to trigger the issue, it requires the ability to create user/net namespaces. On non-containerized deployments of Red Hat Enterprise Linux 7.4 and later, it is recommended to disable user namespaces by setting user.max_user_namespaces to 0: # echo "user.max_user_namespaces=0" > /etc/sysctl.d/userns.conf # sysctl -p /etc/sysctl.d/userns.conf On containerized deployments, such as Red Hat OpenShift Container Platform, do not use this mitigation as the functionality is needed to be enabled.

🔗 References (6)