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Unscored CVE-2025-21872 EUVD-2025-8497GHSA-9pcq-fqff-43qc

efi: Don't map the entire mokvar table to determine its size

Published Mar 27, 2025 · Updated Nov 5, 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-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.4 Package: linux-aws-5.8 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-fips Package: linux-aws-hwe Package: linux-azure Package: linux-azure-4.15 Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 Package: linux-azure-5.8 Package: linux-azure-6.11 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-5.15 Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.2 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-4.15 Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.11 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-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.11 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-5.15 Package: linux-ibm-5.4 Package: linux-ibm-6.8 Package: linux-intel Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-iot Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 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-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx 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-6.5 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-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.4 Package: linux-oracle-5.8 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 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 Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

efi: Don't map the entire mokvar table to determine its size

Currently, when validating the mokvar table, we (re)map the entire table
on each iteration of the loop, adding space as we discover new entries.
If the table grows over a certain size, this fails due to limitations of
early_memmap(), and we get a failure and traceback:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:139 __early_ioremap+0xef/0x220
...
Call Trace:
<TASK>
? __early_ioremap+0xef/0x220
? __warn.cold+0x93/0xfa
? __early_ioremap+0xef/0x220
? report_bug+0xff/0x140
? early_fixup_exception+0x5d/0xb0
? early_idt_handler_common+0x2f/0x3a
? __early_ioremap+0xef/0x220
? efi_mokvar_table_init+0xce/0x1d0
? setup_arch+0x864/0xc10
? start_kernel+0x6b/0xa10
? x86_64_start_reservations+0x24/0x30
? x86_64_start_kernel+0xed/0xf0
? common_startup_64+0x13e/0x141
</TASK>
---[ end trace 0000000000000000 ]---
mokvar: Failed to map EFI MOKvar config table pa=0x7c4c3000, size=265187.

Mapping the entire structure isn't actually necessary, as we don't ever
need more than one entry header mapped at once.

Changes efi_mokvar_table_init() to only map each entry header, not the
entire table, when determining the table size. Since we're not mapping
any data past the variable name, it also changes the code to enforce
that each variable name is NUL terminated, rather than attempting to
verify it in place.

Affected products

VendorProductAffectedFixed
Linux Linux 5.10 5.10.235

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.

Debian

Security tracker ↗
ReleasePackageFixed inAdvisory
Debian 14 linux 6.12.19-1 —
Debian 13 linux 6.12.19-1 —
Debian 12 linux No fix yet —
Debian 11 linux 5.10.237-1 DLA-4178-1

Ubuntu

Security tracker ↗
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield No fix yet —
Ubuntu 24.04 LTS linux 6.8.0-84.84 USN-7764-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1039.41 USN-7764-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1038.44 USN-7802-1
Ubuntu 24.04 LTS linux-azure-nvidia 6.8.0-1025.27 USN-7809-1
Ubuntu 24.04 LTS linux-gcp 6.8.0-1040.42 USN-7764-1
Ubuntu 24.04 LTS linux-gcp-6.11 +1 6.11.0-1015.15~24.04.1 USN-7521-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1036.40 USN-7764-1
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1023.25 USN-7764-1
Ubuntu 24.04 LTS linux-hwe-6.11 6.11.0-26.26~24.04.1 USN-7521-1
Ubuntu 24.04 LTS linux-ibm 6.8.0-1037.37 USN-7779-1
Ubuntu 24.04 LTS linux-intel +4 No fix yet —
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-84.84.1 USN-7764-1
Ubuntu 24.04 LTS linux-lowlatency-hwe-6.11 6.11.0-1014.15~24.04.1 USN-7521-3
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1039.42 USN-7765-1
Ubuntu 24.04 LTS linux-nvidia-6.11 6.11.0-1010.10 —
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1039.42.1 USN-7765-1
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1010.10 —
Ubuntu 24.04 LTS linux-oem-6.11 6.11.0-1022.22 USN-7521-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1037.38 USN-7801-2
Ubuntu 24.04 LTS linux-raspi 6.8.0-1039.43 USN-7790-1
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1018.19 —
Ubuntu 22.04 LTS linux +49 No fix yet —
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1039.41~22.04.1 USN-7766-1
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1036.42~22.04.1 USN-7802-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1040.42~22.04.1 USN-7766-1
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-85.85~22.04.1 USN-7801-1, USN-7764-2
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1037.37~22.04.1 USN-7779-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-84.84.1~22.04.1 USN-7764-1
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1039.42~22.04.1 USN-7765-1
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1037.38~22.04.1 USN-7801-3
Ubuntu 22.04 LTS linux-riscv-6.8 6.8.0-84.84~22.04.1 —
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Show 12 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-raspi-realtime 6.8.0-2030.31 USN-7800-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1034.35 USN-7767-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime +1 No fix yet —
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1034.35~22.04.1 USN-7767-2
Ubuntu Pro FIPS-updates 24.04 LTS linux-aws-fips 6.8.0-1039.41+fips1 —
Ubuntu Pro FIPS-updates 24.04 LTS linux-azure-fips 6.8.0-1040.46+fips1 —
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-84.84+fips1 —
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips 6.8.0-1040.42+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux +21 No fix yet —
Ubuntu Pro 18.04 LTS linux +12 No fix yet —
Ubuntu Pro 16.04 LTS linux-gcp +4 No fix yet —
Ubuntu Pro 14.04 LTS linux-azure No fix yet —

SUSE

Security tracker ↗
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +5 6.4.0-150700.53.11.1 SUSE-SU-2025:02997-1
SLES 15 SP7 kernel-azure +2 6.4.0-150700.20.11.1 SUSE-SU-2025:03011-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.11.1.150700.17.9.4 SUSE-SU-2025:02997-1
SLES 15 SP7 kernel-docs 6.4.0-150700.53.11.3 SUSE-SU-2025:02997-1
SLES 15 SP6 kernel-64kb +6 6.4.0-150600.23.65.1 SUSE-SU-2025:02996-1
SLES 15 SP6 kernel-azure +2 6.4.0-150600.8.48.1 SUSE-SU-2025:02969-1
SLES 15 SP6 kernel-coco +3 6.4.0-15061.28.coco15sp6.1 SUSE-SU-2025:02923-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.65.1.150600.12.28.4 SUSE-SU-2025:02996-1
Show 6 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLE Micro 6.1 kernel-default-base 6.4.0-32.1.21.10 SUSE-SU-2025:20602-1
SLE Micro 6.1 kernel-rt +1 6.4.0-35.1 SUSE-SU-2025:20601-1
SLE Micro 6.1 kernel-source +2 6.4.0-32.1 SUSE-SU-2025:20602-1
SLE Micro 6.0 kernel-default-base 6.4.0-32.1.21.10 SUSE-SU-2025:20586-1
SLE Micro 6.0 kernel-rt +1 6.4.0-35.1 SUSE-SU-2025:20577-1
SLE Micro 6.0 kernel-source +2 6.4.0-32.1 SUSE-SU-2025:20586-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.11.1 SUSE-SU-2025:02997-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_3 1-150700.1.5.1 SUSE-SU-2025:02853-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_3 1-150700.15.3.4 SUSE-SU-2025:02997-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.65.1 SUSE-SU-2025:02996-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_14 1-150600.1.5.1 SUSE-SU-2025:03023-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_14 1-150600.13.3.4 SUSE-SU-2025:02996-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.13.1 SUSE-SU-2025:02853-1
SUSE Real Time Module 15 SP6 kernel-rt +3 6.4.0-150600.10.49.1 SUSE-SU-2025:03023-1

openSUSE

Security tracker ↗
ReleasePackageFixed inAdvisory
openSUSE Leap 15.6 dtb-aarch64 +10 6.4.0-150600.23.65.1 SUSE-SU-2025:02996-1
openSUSE Leap 15.6 kernel-azure +2 6.4.0-150600.8.48.1 SUSE-SU-2025:02969-1
openSUSE Leap 15.6 kernel-default-base 6.4.0-150600.23.65.1.150600.12.28.4 SUSE-SU-2025:02996-1
openSUSE Leap 15.6 kernel-rt +3 6.4.0-150600.10.49.1 SUSE-SU-2025:03023-1

Azure Linux

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

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-101.33.4.3.el10uek ELSA-2025-20530, ELSA-2025-20480

Advisories 31

References