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OpenAdvisories
High · 7.1 CVE-2025-21920 EUVD-2025-9401GHSA-p79h-jcrm-6qrc

vlan: enforce underlying device type

Published Apr 1, 2025 · Updated May 11, 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-5.19 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-lts-xenial 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:

vlan: enforce underlying device type

Currently, VLAN devices can be created on top of non-ethernet devices.

Besides the fact that it doesn't make much sense, this also causes a
bug which leaks the address of a kernel function to usermode.

When creating a VLAN device, we initialize GARP (garp_init_applicant)
and MRP (mrp_init_applicant) for the underlying device.

As part of the initialization process, we add the multicast address of
each applicant to the underlying device, by calling dev_mc_add.

__dev_mc_add uses dev->addr_len to determine the length of the new
multicast address.

This causes an out-of-bounds read if dev->addr_len is greater than 6,
since the multicast addresses provided by GARP and MRP are only 6
bytes long.

This behaviour can be reproduced using the following commands:

ip tunnel add gretest mode ip6gre local ::1 remote ::2 dev lo
ip l set up dev gretest
ip link add link gretest name vlantest type vlan id 100

Then, the following command will display the address of garp_pdu_rcv:

ip maddr show | grep 01:80:c2:00:00:21

Fix the bug by enforcing the type of the underlying device during VLAN
device initialization.

Affected products

VendorProductAffectedFixed
Linux Linux 2.6.35 5.4.291

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 6.12.19-1 —
Debian 13 linux 6.12.19-1 —
Debian 12 linux 6.1.133-1 DSA-5900-1
Debian 11 linux 5.10.237-1 DLA-4178-1
Debian 11 linux-6.1 6.1.137-1~deb11u1 DLA-4193-1
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1066.68 —
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-6.11 6.11.0-1018.18~24.04.1 USN-7628-1
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 6.11.0-1016.16~24.04.1 USN-7605-1
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 6.11.0-28.28~24.04.1 USN-7605-1
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 6.11.0-1015.16~24.04.2 USN-7605-2
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1039.42 USN-7765-1
Ubuntu 24.04 LTS linux-nvidia-6.11 6.11.0-1012.12 —
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 6.11.0-1024.24 USN-7606-1
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 +1 5.15.0-140.150 USN-7510-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1084.91 USN-7510-7
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 5.15.0-1089.98 USN-7510-3
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1036.42~22.04.1 USN-7802-1
Ubuntu 22.04 LTS linux-azure-fde 5.15.0-1089.98.1 —
Ubuntu 22.04 LTS linux-gcp 5.15.0-1083.92 USN-7511-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1040.42~22.04.1 USN-7766-1
Ubuntu 22.04 LTS linux-gke +1 5.15.0-1081.87 USN-7511-3, USN-7510-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1066.74 USN-7510-1
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 5.15.0-1076.79 USN-7510-1
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1037.37~22.04.1 USN-7779-1
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1079.85 USN-7510-1
Ubuntu 22.04 LTS linux-kvm 5.15.0-1080.85 USN-7510-1
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 5.15.0-1078.79 USN-7510-1
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1039.42~22.04.1 USN-7765-1
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1037.37 USN-7510-3
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1026.26 USN-7510-7
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1037.38~22.04.1 USN-7801-3
Ubuntu 22.04 LTS linux-raspi 5.15.0-1078.81 USN-7510-7
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 22.04 LTS linux-riscv-6.8 6.8.0-84.84~22.04.1 —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1050.54 USN-7602-1
Ubuntu 20.04 LTS linux 5.4.0-216.236 USN-7516-1
Ubuntu 20.04 LTS linux-aws 5.4.0-1146.156 USN-7516-9
Ubuntu 20.04 LTS linux-aws-5.15 5.15.0-1084.91~20.04.1 USN-7510-8
Ubuntu 20.04 LTS linux-azure 5.4.0-1151.158 USN-7516-3
Ubuntu 20.04 LTS linux-azure-5.15 5.15.0-1089.98~20.04.1 USN-7510-3
Ubuntu 20.04 LTS linux-bluefield 5.4.0-1105.112 USN-7517-3
Ubuntu 20.04 LTS linux-gcp 5.4.0-1149.158 USN-7516-1
Ubuntu 20.04 LTS linux-gcp-5.15 5.15.0-1083.92~20.04.1 USN-7512-1
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Ubuntu 20.04 LTS linux-ibm 5.4.0-1092.97 USN-7516-6
Ubuntu 20.04 LTS linux-ibm-5.15 5.15.0-1076.79~20.04.1 USN-7510-1
Ubuntu 20.04 LTS linux-intel-iotg-5.15 5.15.0-1079.85~20.04.1 USN-7510-7
Ubuntu 20.04 LTS linux-kvm 5.4.0-1133.142 USN-7516-3
Ubuntu 20.04 LTS linux-lowlatency-hwe-5.15 5.15.0-140.150~20.04.1 USN-7510-1
Ubuntu 20.04 LTS linux-oracle 5.4.0-1144.154 USN-7516-1
Ubuntu 20.04 LTS linux-oracle-5.15 5.15.0-1081.87~20.04.1 USN-7510-1
Ubuntu 20.04 LTS linux-raspi 5.4.0-1129.142 USN-7539-1
Ubuntu 20.04 LTS linux-riscv-5.15 5.15.0-1079.83~20.04.1 —
Ubuntu 20.04 LTS linux-xilinx-zynqmp 5.4.0-1064.68 USN-7517-1
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Show 16 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-intel-iot-realtime 5.15.0-1077.79 USN-7510-4
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1084.93 USN-7510-4
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1034.35~22.04.1 USN-7767-2
Ubuntu Pro FIPS 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 16.04 LTS linux-fips No fix yet —
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-aws-fips 5.15.0-1084.91+fips1 USN-7510-6
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1089.98+fips1 USN-7510-5
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-140.150+fips1 USN-7510-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1083.92+fips1 USN-7511-2
Ubuntu Pro FIPS-updates 20.04 LTS linux-aws-fips 5.4.0-1146.156+fips1 USN-7516-8
Ubuntu Pro FIPS-updates 20.04 LTS linux-azure-fips 5.4.0-1151.158+fips1 USN-7518-1
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips 5.4.0-1120.130 USN-7516-8
Ubuntu Pro FIPS-updates 20.04 LTS linux-gcp-fips 5.4.0-1149.158+fips1 USN-7516-2
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 16.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux-hwe-5.15 5.15.0-142.152~20.04.1 USN-7593-1
Ubuntu Pro 20.04 LTS linux-iot 5.4.0-1051.54 USN-7640-1
Ubuntu Pro 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1039.39~20.04.1 —
Ubuntu Pro 18.04 LTS linux +5 No fix yet —
Ubuntu Pro 18.04 LTS linux-aws-5.4 5.4.0-1146.156~18.04.1 USN-7516-7
Ubuntu Pro 18.04 LTS linux-azure-5.4 5.4.0-1151.158~18.04.1 USN-7516-1
Ubuntu Pro 18.04 LTS linux-gcp-5.4 5.4.0-1149.158~18.04.1 USN-7516-1
Ubuntu Pro 18.04 LTS linux-hwe-5.4 5.4.0-216.236~18.04.1 USN-7516-5
Ubuntu Pro 18.04 LTS linux-ibm-5.4 5.4.0-1092.97~18.04.1 USN-7517-2
Ubuntu Pro 18.04 LTS linux-oracle-5.4 5.4.0-1144.154~18.04.1 USN-7516-4
Ubuntu Pro 18.04 LTS linux-raspi-5.4 5.4.0-1129.142~18.04.1 USN-7540-1
Ubuntu Pro 16.04 LTS linux +7 No fix yet —
Ubuntu Pro 14.04 LTS linux +3 No fix yet —
ReleasePackageFixed inAdvisory
RHEL 9 rv +77 5.14.0-570.21.1.el9_6 RHSA-2025:8643

AlmaLinux

Errata ↗
ReleasePackageFixed inAdvisory
AlmaLinux 9 rv +75 5.14.0-570.21.1.el9_6 ALSA-2025:8643

Rocky Linux

Errata ↗
ReleasePackageFixed inAdvisory
Rocky Linux 9 kernel 5.14.0-570.21.1.el9_6 RLSA-2025:8643
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +6 6.4.0-150700.53.6.1 SUSE-SU-2025:02307-1
SLES 15 SP7 kernel-azure +2 6.4.0-150700.20.6.1 SUSE-SU-2025:02254-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.6.1.150700.17.6.1 SUSE-SU-2025:02307-1
SLES 15 SP6 kernel-64kb +3 6.4.0-150600.23.60.4 SUSE-SU-2025:02538-1
SLES 15 SP6 kernel-azure +2 6.4.0-150600.8.43.1 SUSE-SU-2025:02249-1
SLES 15 SP6 kernel-coco +3 6.4.0-15061.28.coco15sp6.1 SUSE-SU-2025:02923-1
SLES 15 SP6 kernel-default 6.4.0-150600.23.60.5 SUSE-SU-2025:02538-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.60.5.150600.12.26.4 SUSE-SU-2025:02538-1
SLES 15 SP6 kernel-docs +1 6.4.0-150600.23.60.3 SUSE-SU-2025:02538-1
SLES 12 SP5 kernel-syms +2 4.12.14-122.266.1 SUSE-SU-2025:02334-1
Show 7 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLE Micro 6.1 kernel-default-base 6.4.0-31.1.21.9 SUSE-SU-2025:20475-1
SLE Micro 6.1 kernel-rt +1 6.4.0-34.1 SUSE-SU-2025:20483-1
SLE Micro 6.1 kernel-source +2 6.4.0-31.1 SUSE-SU-2025:20475-1
SLE Micro 6.0 kernel-default-base 6.4.0-31.1.21.9 SUSE-SU-2025:20493-1
SLE Micro 6.0 kernel-rt +1 6.4.0-34.1 SUSE-SU-2025:20498-1
SLE Micro 6.0 kernel-source +2 6.4.0-31.1 SUSE-SU-2025:20493-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.6.1 SUSE-SU-2025:02307-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_2 1-150700.1.5.1 SUSE-SU-2025:02333-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_2 1-150700.15.3.1 SUSE-SU-2025:02307-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.60.5 SUSE-SU-2025:02538-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_13 1-150600.1.5.1 SUSE-SU-2025:02335-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_13 1-150600.13.6.4 SUSE-SU-2025:02538-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.266.1 SUSE-SU-2025:02334-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_70 1-8.5.1 SUSE-SU-2025:02334-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.8.1 SUSE-SU-2025:02333-1
SUSE Real Time Module 15 SP6 kernel-rt +3 6.4.0-150600.10.44.1 SUSE-SU-2025:02335-1
ReleasePackageFixed inAdvisory
openSUSE Leap 15.6 dtb-aarch64 +2 6.4.0-150600.23.60.3 SUSE-SU-2025:02538-1
openSUSE Leap 15.6 kernel-64kb +5 6.4.0-150600.23.60.4 SUSE-SU-2025:02538-1
openSUSE Leap 15.6 kernel-azure +2 6.4.0-150600.8.43.1 SUSE-SU-2025:02249-1
openSUSE Leap 15.6 kernel-default 6.4.0-150600.23.60.5 SUSE-SU-2025:02538-1
openSUSE Leap 15.6 kernel-default-base 6.4.0-150600.23.60.5.150600.12.26.4 SUSE-SU-2025:02538-1
openSUSE Leap 15.6 kernel-obs-qa 6.4.0-150600.23.60.2 SUSE-SU-2025:02538-1
openSUSE Leap 15.6 kernel-rt +3 6.4.0-150600.10.44.1 SUSE-SU-2025:02335-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.1.131-143.221 1.0-0.amzn2023 ALAS2023-2025-915
Amazon Linux 2023 perf +14 6.1.131-143.221.amzn2023 ALAS2023-2025-915
Amazon Linux 2 kernel-livepatch-4.14.355-277.643 1.0-0.amzn2 ALAS2-2025-2854
Amazon Linux 2 perf +8 4.14.355-277.643.amzn2 ALAS2-2025-2854

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.85.1-2 —
Azure Linux 2 (CBL-Mariner) kernel 5.15.180.1-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-101.33.4.3.el10uek ELSA-2025-20530, ELSA-2025-20480
Oracle Linux 9 rv +28 5.14.0-570.21.1.0.1.el9_6 ELSA-2025-8643

Advisories 50

References