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Unscored CVE-2025-38704 EUVD-2025-26765GHSA-8f3q-p7pf-m5wj

rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access

Published Sep 4, 2025 · Updated Nov 10, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: kernel Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.8 Package: linux-aws-6.14 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-fips Package: linux-azure Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.14 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-azure-nvidia-6.14 Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.14 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.19 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.14 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-6.8 Package: linux-intel Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-lowlatency Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.11 Package: linux-oem-6.14 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.3 Package: linux-oracle-5.8 Package: linux-oracle-6.14 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-raspi Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.14 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Platform: Linux Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

In the Linux kernel, the following vulnerability has been resolved:

rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access

In the preparation stage of CPU online, if the corresponding
the rdp's->nocb_cb_kthread does not exist, will be created,
there is a situation where the rdp's rcuop kthreads creation fails,
and then de-offload this CPU's rdp, does not assign this CPU's
rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and
rdp's->rdp_gp->nocb_gp_kthread is still valid.

This will cause the subsequent re-offload operation of this offline
CPU, which will pass the conditional check and the kthread_unpark()
will access invalid rdp's->nocb_cb_kthread pointer.

This commit therefore use rdp's->nocb_gp_kthread instead of
rdp_gp's->nocb_gp_kthread for safety check.

Affected products

VendorProductAffectedFixed
Linux Linux 6.0 6.1.167

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 linux 6.16.3-1 —
Debian 13 linux 6.12.43-1 —
Debian 12 linux 6.1.170-1 —
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1016.20 —
Ubuntu 25.10 linux-azure-fde No fix yet —
Ubuntu 24.04 LTS linux 6.8.0-100.100 USN-8028-1
Ubuntu 24.04 LTS linux-aws +1 6.8.0-1046.49 USN-8028-5
Ubuntu 24.04 LTS linux-azure 6.8.0-1046.52 USN-8074-1
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1046.53 —
Ubuntu 24.04 LTS linux-azure-nvidia 6.8.0-1039.42 —
Ubuntu 24.04 LTS linux-gcp 6.8.0-1047.50 USN-8031-3
Ubuntu 24.04 LTS linux-gke 6.8.0-1043.48 USN-8031-3
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1030.33 USN-8028-5
Ubuntu 24.04 LTS linux-ibm 6.8.0-1044.44 USN-8028-8
Ubuntu 24.04 LTS linux-intel +19 No fix yet —
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-100.100.1 USN-8052-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1046.49.1 USN-8028-7
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1020.20 —
Ubuntu 24.04 LTS linux-oracle 6.8.0-1043.44 USN-8028-5
Ubuntu 24.04 LTS linux-raspi 6.8.0-1047.51 USN-8028-1
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1023.24 USN-8052-2
Ubuntu 22.04 LTS linux-aws-6.8 +1 6.8.0-1046.49~22.04.1 USN-8028-5
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1051.57~22.04.1 USN-8126-1
Ubuntu 22.04 LTS linux-azure-fde-6.8 6.8.0-1046.53~22.04.1 —
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1047.50~22.04.2 USN-8031-1
Ubuntu 22.04 LTS linux-hwe-6.8 +1 6.8.0-100.100~22.04.1 USN-8028-6
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1044.44~22.04.1 USN-8028-8
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-100.100.1~22.04.1 USN-8028-6
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1043.44~22.04.1 USN-8028-5
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Show 5 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-raspi-realtime 6.8.0-2037.38 USN-8028-3
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1041.42 USN-8028-3
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 No fix yet —
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1041.42~22.04.1 USN-8028-2
Ubuntu Pro FIPS-updates 24.04 LTS linux-aws-fips 6.8.0-1046.49+fips1 USN-8028-4
Ubuntu Pro FIPS-updates 24.04 LTS linux-azure-fips 6.8.0-1046.52+fips1 USN-8074-2
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-100.100+fips1 USN-8028-4
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips 6.8.0-1047.50+fips1 USN-8031-2
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +7 6.4.0-150700.53.84.1 SUSE-SU-2026:4706-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.84.1.150700.17.47.1 SUSE-SU-2026:4706-1
SLES 15 SP6 kernel-64kb +6 6.4.0-150600.23.138.1 SUSE-SU-2026:4660-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.138.1.150600.12.64.1 SUSE-SU-2026:4660-1
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 kernel-64kb +8 6.12.0-160000.9.1 SUSE-SU-2026:20220-1
SLES for SAP 16.0 kernel-default-base 6.12.0-160000.9.1.160000.2.6 SUSE-SU-2026:20220-1
SLES for SAP 15 SP6 kernel-default-base 6.4.0-150600.23.138.1.150600.12.64.1 SUSE-SU-2026:4660-1
SLES for SAP 15 SP6 kernel-docs +4 6.4.0-150600.23.138.1 SUSE-SU-2026:4660-1
SLES 16.0 kernel-64kb +8 6.12.0-160000.9.1 SUSE-SU-2026:20228-1, SUSE-SU-2026:20220-1
SLES 16.0 kernel-default-base 6.12.0-160000.9.1.160000.2.6 SUSE-SU-2026:20220-1
SLE Micro 6.2 kernel-default-base 6.12.0-160000.9.1.160000.2.6 SUSE-SU-2026:20207-1
SLE Micro 6.2 kernel-rt +5 6.12.0-160000.9.1 SUSE-SU-2026:20564-1, SUSE-SU-2026:20207-1
SLE Micro 6.2 podman 5.4.2-160000.6.1 SUSE-SU-2026:24182-1
SLE Micro 6.1 kernel-default-base 6.4.0-159998.53.1.159998.21.38 SUSE-SU-2026:24181-1
SLE Micro 6.1 kernel-rt +4 6.4.0-159998.53.1 SUSE-SU-2026:24182-1, SUSE-SU-2026:24181-1
SLE Micro 6.0 kernel-default-base 6.4.0-159998.53.1.159998.21.38 SUSE-SU-2026:24315-1
SLE Micro 6.0 kernel-rt +4 6.4.0-159998.53.1 SUSE-SU-2026:24316-1, SUSE-SU-2026:24315-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.84.1 SUSE-SU-2026:4706-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_21 1-150700.1.3.1 SUSE-SU-2026:4640-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_22 1-150700.15.3.1 SUSE-SU-2026:4706-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.138.1 SUSE-SU-2026:4660-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_32 1-150600.13.3.1 SUSE-SU-2026:4660-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.78.1 SUSE-SU-2026:4640-1
ReleasePackageFixed inAdvisory
openSUSE Leap 16.0 kernel-default-base 6.12.0-160000.9.1.160000.2.6 openSUSE-SU-2026:20145-1
openSUSE Leap 16.0 kernel-rt +11 6.12.0-160000.9.1 openSUSE-SU-2026:20145-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.12.46-66.121 +1 1:1.0-0.amzn2023 ALAS2023-2026-1681, ALAS2023-2025-1208
Amazon Linux 2023 perf +14 1:6.1.168-202.320.amzn2023 ALAS2023-2026-1681
Amazon Linux 2023 perf6.12 +14 1:6.12.46-66.121.amzn2023 ALAS2023-2025-1208

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.130.1-3 —
Azure Linux 2 (CBL-Mariner) kernel No fix yet —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-104.43.4.2.el10uek ELSA-2025-20662

Advisories 40

References