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Critical · 9.8 CVE-2026-31668 EUVD-2026-25561GHSA-r2p4-96h8-cc74

seg6: separate dst_cache for input and output paths in seg6 lwtunnel

Published Apr 24, 2026 · Updated Oct 19, 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-6.14 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-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-6.14 Package: linux-azure-6.17 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-6.14 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-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-6.14 Package: linux-gcp-6.17 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-6.14 Package: linux-hwe-6.17 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-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-6.17 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-6.14 Package: linux-oem-6.17 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-6.14 Package: linux-oracle-6.17 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-6.14 Package: linux-realtime-6.17 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-6.14 Package: linux-riscv-6.17 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:

seg6: separate dst_cache for input and output paths in seg6 lwtunnel

The seg6 lwtunnel uses a single dst_cache per encap route, shared
between seg6_input_core() and seg6_output_core(). These two paths
can perform the post-encap SID lookup in different routing contexts
(e.g., ip rules matching on the ingress interface, or VRF table
separation). Whichever path runs first populates the cache, and the
other reuses it blindly, bypassing its own lookup.

Fix this by splitting the cache into cache_input and cache_output,
so each path maintains its own cached dst independently.

Affected products

VendorProductAffectedFixed
Linux Linux 4.10 5.10.253

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 6.19.13-1 —
Debian 13 linux 6.12.85-1 —
Debian 12 linux 6.1.170-1 —
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1026.30 —
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1095.97 —
Ubuntu 26.04 LTS linux-nvidia 7.0.0-1006.6 —
Ubuntu 25.10 linux 6.17.0-40.40 USN-8490-1
Ubuntu 25.10 linux-aws 6.17.0-1019.19 USN-8490-1
Ubuntu 25.10 linux-azure +1 No fix yet —
Ubuntu 25.10 linux-gcp 6.17.0-1020.22 USN-8490-1
Ubuntu 25.10 linux-oracle 6.17.0-1018.18 USN-8490-1
Ubuntu 25.10 linux-raspi 6.17.0-1021.21 USN-8546-1
Ubuntu 25.10 linux-realtime 6.17.0-1017.19 USN-8490-2
Ubuntu 25.10 linux-riscv 6.17.0-40.40.1 —
Ubuntu 24.04 LTS linux 6.8.0-134.134 USN-8492-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1060.63 USN-8492-1
Ubuntu 24.04 LTS linux-aws-6.17 6.17.0-1019.19~24.04.1 USN-8490-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1063.71 USN-8606-1
Ubuntu 24.04 LTS linux-azure-6.17 6.17.0-1021.21~24.04.1 USN-8604-1
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1062.69 USN-8607-1
Ubuntu 24.04 LTS linux-gcp 6.8.0-1063.69 USN-8492-1
Ubuntu 24.04 LTS linux-gcp-6.17 6.17.0-1020.22~24.04.1 USN-8490-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1058.64 USN-8492-2
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1045.48 USN-8492-2
Ubuntu 24.04 LTS linux-hwe-6.17 6.17.0-40.40~24.04.1 USN-8545-1
Ubuntu 24.04 LTS linux-ibm 6.8.0-1060.61 USN-8492-1
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-134.134.1 USN-8497-1
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1058.61 USN-8492-1
Ubuntu 24.04 LTS linux-nvidia-6.17 6.17.0-1026.26 USN-8508-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1058.61.1 USN-8492-2
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1029.30 USN-8498-1
Ubuntu 24.04 LTS linux-oem-6.17 6.17.0-1028.28 USN-8491-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1057.58 USN-8492-1
Ubuntu 24.04 LTS linux-oracle-6.17 +1 6.17.0-1018.18~24.04.1 USN-8605-1, USN-8490-1
Ubuntu 24.04 LTS linux-raspi 6.8.0-1060.64 USN-8492-4
Ubuntu 24.04 LTS linux-riscv +20 No fix yet —
Ubuntu 24.04 LTS linux-vmware 6.8.0-1008.8 —
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1032.33 USN-8499-1
Show 17 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 22.04 LTS linux 5.15.0-185.195 USN-8493-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1111.118 USN-8493-1
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1060.63~22.04.1 USN-8492-2
Ubuntu 22.04 LTS linux-azure +1 5.15.0-1116.125 USN-8493-1
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1063.71~22.04.1 USN-8606-1
Ubuntu 22.04 LTS linux-azure-fde-6.8 6.8.0-1062.69~22.04.1 USN-8609-1
Ubuntu 22.04 LTS linux-gcp 5.15.0-1111.121 USN-8493-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1063.69~22.04.1 USN-8492-2
Ubuntu 22.04 LTS linux-gke 5.15.0-1107.113 USN-8493-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1094.102 USN-8493-1
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-136.136~22.04.1 USN-8619-1
Ubuntu 22.04 LTS linux-ibm 5.15.0-1105.109 USN-8493-1
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1060.61~22.04.1 USN-8492-2
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1106.112 USN-8493-1
Ubuntu 22.04 LTS linux-kvm 5.15.0-1103.108 USN-8493-1
Ubuntu 22.04 LTS linux-lowlatency 5.15.0-183.193 USN-8493-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-134.134.1~22.04.1 USN-8497-1
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1106.107 USN-8493-1
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1058.61~22.04.1 USN-8492-1
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1063.63 USN-8493-1
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1052.52 USN-8493-1
Ubuntu 22.04 LTS linux-oracle 5.15.0-1108.114 USN-8493-1
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1057.58~22.04.1 USN-8492-2
Ubuntu 22.04 LTS linux-raspi 5.15.0-1105.108 USN-8527-1
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 22.04 LTS linux-riscv-6.8 6.8.0-134.134~22.04.1 —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1074.78 USN-8528-1
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
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 6.8.0-2049.50 USN-8492-3
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1055.56 USN-8492-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.17 6.17.0-1017.19~24.04.1 USN-8490-2
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1103.105 USN-8493-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1110.119 USN-8493-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1055.56~22.04.1 USN-8492-1
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-updates 24.04 LTS linux-aws-fips 6.8.0-1060.63+fips1 USN-8492-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-azure-fips 6.8.0-1062.69+fips1 USN-8492-5
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-134.134+fips1 USN-8492-5
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips 6.8.0-1063.69+fips1 USN-8492-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1111.118+fips1 USN-8493-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1116.125+fips1 USN-8547-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-185.195+fips1 USN-8493-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1111.121+fips1 USN-8493-1
Ubuntu Pro FIPS-updates 20.04 LTS linux-aws-fips 5.4.0-1163.174+fips1 USN-8715-2
Ubuntu Pro FIPS-updates 20.04 LTS linux-azure-fips 5.4.0-1167.173+fips1 USN-8666-2
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips 5.4.0-1136.146 USN-8666-1
Ubuntu Pro FIPS-updates 20.04 LTS linux-gcp-fips 5.4.0-1165.174+fips1 USN-8666-3
Ubuntu Pro FIPS-updates 18.04 LTS linux-aws-fips 4.15.0-2133.139 USN-8633-1
Ubuntu Pro FIPS-updates 18.04 LTS linux-azure-fips 4.15.0-2113.119 USN-8633-1
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips 4.15.0-1150.162 USN-8633-1
Ubuntu Pro FIPS-updates 18.04 LTS linux-gcp-fips 4.15.0-2096.102 USN-8633-1
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux 5.4.0-234.254 USN-8666-1
Ubuntu Pro 20.04 LTS linux-aws 5.4.0-1162.173 USN-8666-1
Ubuntu Pro 20.04 LTS linux-aws-5.15 5.15.0-1111.118~20.04.1 USN-8493-1
Ubuntu Pro 20.04 LTS linux-azure 5.4.0-1167.173 USN-8666-1
Ubuntu Pro 20.04 LTS linux-azure-5.15 +1 5.15.0-1116.125~20.04.1 USN-8493-1
Ubuntu Pro 20.04 LTS linux-bluefield 5.4.0-1121.128 USN-8666-1
Ubuntu Pro 20.04 LTS linux-gcp 5.4.0-1165.174 USN-8666-1
Ubuntu Pro 20.04 LTS linux-gcp-5.15 5.15.0-1111.121~20.04.1 USN-8547-1
Ubuntu Pro 20.04 LTS linux-hwe-5.15 5.15.0-185.195~20.04.1 USN-8493-1
Ubuntu Pro 20.04 LTS linux-ibm 5.4.0-1108.113 USN-8666-1
Ubuntu Pro 20.04 LTS linux-ibm-5.15 +1 5.15.0-1105.109~20.04.1 USN-8493-1
Ubuntu Pro 20.04 LTS linux-intel-iotg-5.15 5.15.0-1106.112~20.04.1 USN-8547-1
Ubuntu Pro 20.04 LTS linux-iot 5.4.0-1066.69 USN-8666-1
Ubuntu Pro 20.04 LTS linux-kvm 5.4.0-1149.158 USN-8667-1
Ubuntu Pro 20.04 LTS linux-lowlatency-hwe-5.15 5.15.0-183.193~20.04.1 USN-8493-1
Ubuntu Pro 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1063.63~20.04.1 USN-8493-1
Ubuntu Pro 20.04 LTS linux-oracle 5.4.0-1160.170 USN-8666-1
Ubuntu Pro 20.04 LTS linux-oracle-5.15 5.15.0-1108.114~20.04.1 USN-8493-2
Ubuntu Pro 20.04 LTS linux-raspi 5.4.0-1145.158 USN-8666-1
Ubuntu Pro 20.04 LTS linux-xilinx-zynqmp 5.4.0-1080.84 USN-8666-1
Ubuntu Pro 18.04 LTS linux 4.15.0-254.266 USN-8633-1
Ubuntu Pro 18.04 LTS linux-aws 4.15.0-1195.208 USN-8633-1
Ubuntu Pro 18.04 LTS linux-aws-5.4 5.4.0-1162.173~18.04.1 USN-8666-1
Ubuntu Pro 18.04 LTS linux-azure-4.15 4.15.0-1205.220 USN-8633-1
Ubuntu Pro 18.04 LTS linux-azure-5.4 5.4.0-1167.173~18.04.1 USN-8666-2
Ubuntu Pro 18.04 LTS linux-gcp-4.15 4.15.0-1188.205 USN-8633-1
Ubuntu Pro 18.04 LTS linux-gcp-5.4 5.4.0-1165.174~18.04.1 USN-8666-1
Ubuntu Pro 18.04 LTS linux-hwe-5.4 5.4.0-234.254~18.04.1 USN-8666-1
Ubuntu Pro 18.04 LTS linux-ibm-5.4 5.4.0-1108.113~18.04.1 USN-8666-1
Ubuntu Pro 18.04 LTS linux-kvm 4.15.0-1177.182 USN-8633-1
Ubuntu Pro 18.04 LTS linux-oracle 4.15.0-1158.169 USN-8645-1
Ubuntu Pro 18.04 LTS linux-oracle-5.4 5.4.0-1161.171~18.04.1 USN-8715-1
Ubuntu Pro 18.04 LTS linux-raspi-5.4 5.4.0-1145.158~18.04.1 USN-8666-1
Ubuntu Pro 16.04 LTS linux-aws-hwe 4.15.0-1195.208~16.04.1 USN-8633-2
Ubuntu Pro 16.04 LTS linux-azure 4.15.0-1205.220~16.04.1 USN-8633-2
Ubuntu Pro 16.04 LTS linux-gcp 4.15.0-1188.205~16.04.1 USN-8633-2
Ubuntu Pro 16.04 LTS linux-hwe 4.15.0-254.266~16.04.1 USN-8633-2
Ubuntu Pro 16.04 LTS linux-oracle 4.15.0-1158.169~16.04.1 USN-8645-1
Ubuntu Pro 14.04 LTS linux-azure 4.15.0-1205.220~14.04.1 USN-8635-1
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +7 6.4.0-150700.53.55.1 SUSE-SU-2026:2238-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.55.1.150700.17.33.1 SUSE-SU-2026:2238-1
SLES 12 SP5 kernel-syms +2 4.12.14-122.317.1 SUSE-SU-2026:2450-1
Show 3 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLE Micro 6.2 kernel-syms +1 6.12.0-160000.33.1 SUSE-SU-2026:21834-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.55.1 SUSE-SU-2026:2238-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_15 1-150700.15.3.1 SUSE-SU-2026:2238-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.317.1 SUSE-SU-2026:2450-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_84 1-8.7.1 SUSE-SU-2026:2450-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.18.25-55.108 +2 1:1.0-0.amzn2023 ALAS2023-2026-1695, ALAS2023-2026-1694, ALAS2023-2026-1693
Amazon Linux 2023 perf +11 1:6.1.170-210.320.amzn2023 ALAS2023-2026-1694
Amazon Linux 2023 perf6.12 +11 1:6.12.83-113.160.amzn2023 ALAS2023-2026-1695
Amazon Linux 2023 perf6.18 +11 1:6.18.25-55.108.amzn2023 ALAS2023-2026-1693

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.137.1-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-204.92.4.2.el10uek ELSA-2026-50372

Advisories 44

References