RHSA-2026:9513MediumCVSS 7.5

Red Hat Security Advisory: kernel security update

Published
April 22, 2026
Last Modified
July 30, 2026

🔗 CVE IDs covered (4)

CVE-2025-40064 →CVE-2025-40168 →CVE-2026-23204 →CVE-2026-23231 →

📋 Description

CVE-2025-40064 — kernel: smc: Fix use-after-free in __pnet_find_base_ndev() CVE-2025-40168 — kernel: smc: Use __sk_dst_get() and dst_dev_rcu() in smc_clc_prfx_match() 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 products26

  • Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • bpftool-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • bpftool-debuginfo-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-0:4.18.0-193.195.1.el8_2.src as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-abi-whitelists-0:4.18.0-193.195.1.el8_2.noarch as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-core-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-debug-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-debug-core-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-debug-debuginfo-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-debug-devel-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-debug-modules-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-debug-modules-extra-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-debuginfo-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-debuginfo-common-x86_64-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-devel-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-doc-0:4.18.0-193.195.1.el8_2.noarch as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-modules-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-modules-extra-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-tools-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-tools-debuginfo-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • kernel-tools-libs-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • perf-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • perf-debuginfo-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • python3-perf-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
  • python3-perf-debuginfo-0:4.18.0-193.195.1.el8_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v. 8.2)

✅ 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: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. 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 8, 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 (7)