RHSA-2026:39082HighCVSS 7.8

Red Hat Security Advisory: kernel-rt security update

Published
July 14, 2026
Last Modified
August 26, 2026

🔗 CVE IDs covered (8)

CVE-2026-53166 →CVE-2026-53266 →CVE-2026-53359 →CVE-2025-71066 →CVE-2025-71089 →CVE-2026-31411 →CVE-2026-43499 →CVE-2026-46113 →

📋 Description

CVE-2025-71066 — kernel: net/sched: ets: Always remove class from active list before deleting in ets_qdisc_change CVE-2025-71089 — kernel: iommu: disable SVA when CONFIG_X86 is set CVE-2026-31411 — kernel: net: atm: fix crash due to unvalidated vcc pointer in sigd_send() CVE-2026-43499 — kernel: rtmutex: Use waiter::task instead of current in remove_waiter() CVE-2026-46113 — kernel: KVM: x86: Fix shadow paging use-after-free due to unexpected GFN CVE-2026-53166 — kernel: futex/requeue: Prevent NULL pointer dereference in remove_waiter() on self-deadlock CVE-2026-53266 — kernel: Linux kernel: netfilter: ebtables SNAT target writes to shared memory pages during ARP hardware address rewrite CVE-2026-53359 — kernel: KVM: x86: Fix shadow paging use-after-free due to unexpected role

🎯 Affected products32

  • Red Hat Enterprise Linux NFV (v. 8)
  • Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-0:4.18.0-553.143.1.rt7.484.el8_10.src as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-0:4.18.0-553.143.1.rt7.484.el8_10.src as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-core-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-core-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-core-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-core-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-debuginfo-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-debuginfo-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-devel-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-devel-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-kvm-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-modules-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-modules-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-modules-extra-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-modules-extra-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debuginfo-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debuginfo-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debuginfo-common-x86_64-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debuginfo-common-x86_64-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-devel-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-devel-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-kvm-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-modules-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-modules-0:4.18.0-553.143.1.rt7.484.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • +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. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available. Workaround: See the security bulletin for a detailed mitigation procedure. 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: Disable ARP hardware address rewriting in ebtables SNAT rules, or remove ebtables SNAT rules that operate on ARP traffic on bridge interfaces. Workaround: This vulnerability can be mitigated by disabling nested virtualization. Create a file in `/etc/modprobe.d/` with a descriptive name, such as `cve-2026-53359-mitigation.conf`. In that file, disable nested virtualization for the `kvm_intel` and `kvm_amd` kernel modules: ``` options kvm-intel nested=0 options kvm-amd nested=0 ``` Use `lsmod` to determine if either module is already loaded. If so, remove loaded modules with `modprobe -r`. To validate that nested virtualization is disabled, read the files `/sys/module/kvm_intel/parameters/nested` and `/sys/module/kvm_amd/parameters/nested`. If these modules are loaded, those files should read `N` to indicate that the feature is disabled. In OpenShift 4, a MachineConfig can be utilized to create a modprobe configuration allowing control of the module on applicable nodes. See the following article for an example. https://access.redhat.com/solutions/6979679

🔗 References (11)