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Unscored CVE-2026-64183 EUVD-2026-45868GHSA-wmr2-4wg6-fwrh

efi: Allocate runtime workqueue before ACPI init

Published Jul 19, 2026 · Updated Nov 6, 2026 · Assigned by Linux

Vendor: Linux Product: Linux 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-6.17 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-6.17 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-7.0 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.17 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 Package: linux-azure-fde-7.0 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-6.17 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-7.0 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-6.17 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-7.0 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-6.8 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-6.17 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-7.0 Package: linux-nvidia-bos 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-6.17 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oem-7.0 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-6.17 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-oracle-7.0 Package: linux-raspi Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 Package: linux-realtime-6.17 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-6.17 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-riscv-7.0 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Platform: Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

efi: Allocate runtime workqueue before ACPI init

Since commit

5894cf571e14 ("acpi/prmt: Use EFI runtime sandbox to invoke PRM handlers")

ACPI PRM calls are delegated to a workqueue which runs in a kernel
thread, making it easier to detect and mitigate faulting memory accesses
performed by the firmware.

Rafael reports that such PRM accesses may occur before efisubsys_init()
executes, which is where the workqueue is allocated, leading to NULL
pointer dereferences. Since acpi_init() [which triggers the early PRM
accesses] executes as a subsys_initcall() as well, and has its own
dependencies that may be sensitive to initcall ordering, deferring
acpi_init() is not an option.

So instead, split off the workqueue allocation into its own postcore
initcall, as this is the only missing piece to allow EFI runtime calls
to be made. This ensures that EFI runtime call (including PRM calls) are
accessible to all code running at subsys_initcall() level.

Affected products

VendorProductAffectedFixed
Linux Linux 6.6 6.6.142

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 7.0.12-1 —
Debian 13 linux 6.12.94-1 —
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1030.35 —
Ubuntu 26.04 LTS linux 7.0.0-28.28 —
Ubuntu 26.04 LTS linux-aws +2 7.0.0-1009.9 USN-8618-1, USN-8603-1
Ubuntu 26.04 LTS linux-gcp +1 7.0.0-1008.8 USN-8593-1
Ubuntu 26.04 LTS linux-gke 7.0.0-1003.4 —
Ubuntu 26.04 LTS linux-ibm +1 7.0.0-1010.10 USN-8603-1, USN-8593-1
Ubuntu 26.04 LTS linux-nvidia 7.0.0-1016.16 USN-8663-1
Ubuntu 26.04 LTS linux-nvidia-bos 7.0.0-2016.16 USN-8664-1
Ubuntu 26.04 LTS linux-raspi 7.0.0-1015.15 USN-8618-1
Ubuntu 26.04 LTS linux-riscv +1 7.0.0-28.28.1 —
Ubuntu 24.04 LTS linux 6.8.0-139.139 USN-8729-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1064.67 USN-8729-6
Ubuntu 24.04 LTS linux-azure-7.0 7.0.0-1014.14~24.04.1 USN-8728-2
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1065.72 —
Ubuntu 24.04 LTS linux-azure-fde-7.0 7.0.0-1013.13~24.04.1 —
Ubuntu 24.04 LTS linux-gcp +1 6.8.0-1067.75 USN-8761-1, USN-8729-1
Ubuntu 24.04 LTS linux-gcp-7.0 +1 7.0.0-1011.11~24.04.1 USN-8728-3, USN-8728-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1062.70 USN-8729-1
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1049.53 USN-8729-1
Ubuntu 24.04 LTS linux-hwe-7.0 7.0.0-28.28~24.04.1 —
Ubuntu 24.04 LTS linux-ibm 6.8.0-1064.65 USN-8729-3
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-139.139.1 USN-8729-4
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1062.65 USN-8729-1
Ubuntu 24.04 LTS linux-nvidia-7.0 7.0.0-1016.16~24.04.1 USN-8663-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1062.65.1 USN-8729-1
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1035.38 USN-8781-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1061.64 USN-8802-1
Ubuntu 24.04 LTS linux-raspi 6.8.0-1064.68 USN-8729-1
Ubuntu 24.04 LTS linux-riscv +28 No fix yet —
Ubuntu 24.04 LTS linux-riscv-7.0 7.0.0-28.28.1~24.04.3 —
Ubuntu 24.04 LTS linux-vmware 6.8.0-1008.8 —
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1036.37 USN-8729-3
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1064.67~22.04.1 USN-8729-6
Ubuntu 22.04 LTS linux-azure-fde-6.8 6.8.0-1065.72~22.04.1 —
Ubuntu 22.04 LTS linux-gcp-6.8 +1 6.8.0-1067.75~22.04.1 USN-8761-3, USN-8729-3
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-149.149~22.04.1 USN-9066-1
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1066.67~22.04.1 USN-8906-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-139.139.1~22.04.1 USN-8729-4
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1062.65~22.04.1 USN-8729-1
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1061.64~22.04.1 USN-8802-1
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 22.04 LTS linux-riscv-6.8 6.8.0-139.139~22.04.1 —
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 6.8.0-2053.55 USN-8729-2
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1059.60 USN-8729-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 +1 No fix yet —
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1059.60~22.04.1 USN-8729-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-aws-fips 6.8.0-1064.67+fips1 USN-8729-5
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-139.139+fips1 USN-8729-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips +1 6.8.0-1067.75+fips1 USN-8761-2, USN-8729-1
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +7 6.4.0-150700.53.78.1 SUSE-SU-2026:3790-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.78.1.150700.17.43.2 SUSE-SU-2026:3790-1
Show 7 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 kernel-64kb +8 6.12.0-160000.37.1 SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLES for SAP 16.0 kernel-default-base 6.12.0-160000.37.1.160000.2.19 SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLES 16.0 kernel-64kb +8 6.12.0-160000.37.1 SUSE-SU-2026:23237-1, SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLES 16.0 kernel-default-base 6.12.0-160000.37.1.160000.2.19 SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLE Micro 6.2 kernel-default-base 6.12.0-160000.37.1.160000.2.19 SUSE-SU-2026:23068-1
SLE Micro 6.2 kernel-rt +5 6.12.0-160000.37.1 SUSE-SU-2026:23068-1, SUSE-SU-2026:23066-1
SLE Micro 6.1 kernel-rt +4 6.4.0-51.1 SUSE-SU-2026:23194-1, SUSE-SU-2026:23193-1
SLE Micro 6.0 kernel-rt +4 6.4.0-51.1 SUSE-SU-2026:23244-1, SUSE-SU-2026:23241-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.78.1 SUSE-SU-2026:3790-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_19 1-150700.1.5.1 SUSE-SU-2026:3810-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_20 1-150700.15.3.2 SUSE-SU-2026:3790-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.72.1 SUSE-SU-2026:3810-1
ReleasePackageFixed inAdvisory
openSUSE Leap 16.0 kernel-default-base 6.12.0-160000.37.1.160000.2.19 openSUSE-SU-2026:21555-1
openSUSE Leap 16.0 kernel-rt +11 6.12.0-160000.37.1 openSUSE-SU-2026:21555-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.18.35-68.127 +1 1:1.0-0.amzn2023 ALAS2023-2026-1894, ALAS2023-2026-1881
Amazon Linux 2023 perf6.12 +11 1:6.12.92-122.166.amzn2023 ALAS2023-2026-1894
Amazon Linux 2023 perf6.18 +12 1:6.18.35-68.127.amzn2023 ALAS2023-2026-1881

Advisories 36

References