Improper access control in Linux kernel - CVE-2026-31668

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Main Vulnerability Database Vulnerabilities #VU127730

Improper access control in Linux kernel - CVE-2026-31668

Published: April 25, 2026


Vulnerability identifier: #VU127730
CSH Severity: Low
CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-31668
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to bypass routing policy restrictions.

The vulnerability exists due to improper access control in the seg6 lwtunnel dst_cache handling when processing input and output paths in different routing contexts. A local user can trigger packet processing through one path so that the other path reuses an incorrect cached destination to bypass routing policy restrictions.

The issue occurs because a single destination cache is shared between seg6_input_core() and seg6_output_core(), even though these paths may perform SID lookup under different routing contexts such as ingress-interface-based rules or VRF table separation.


Affected software

Linux kernel
Debian Linux
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Live Patching
Public Cloud Module
Legacy Module
Development Tools Module
Basesystem Module
SUSE Real Time Module
Ubuntu
openEuler
kernel-livepatch-6_4_0-150700_7_54-rt
kernel-livepatch-SLE15-SP7-RT_Update_15-debugsource
kernel-livepatch-6_4_0-150700_7_54-rt-debuginfo
kernel-livepatch-6_4_0-150700_53_55-default-debuginfo
kernel-livepatch-6_4_0-150700_53_55-default
kernel-livepatch-SLE15-SP7_Update_15-debugsource
kernel-tools-devel
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
bpftool
kernel
linux (Ubuntu package)
linux-xilinx-zynqmp (Ubuntu package)
linux-raspi (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux (Debian package)
dlm-kmp-rt
kernel-rt
kernel-source-rt
kernel-devel-rt
gfs2-kmp-rt-debuginfo
cluster-md-kmp-rt
ocfs2-kmp-rt
kernel-syms-rt
gfs2-kmp-rt
cluster-md-kmp-rt-debuginfo
kernel-rt-debuginfo
kernel-rt-devel-debuginfo
dlm-kmp-rt-debuginfo
kernel-rt-devel
ocfs2-kmp-rt-debuginfo
kernel-rt-debugsource
kernel-64kb
kernel-default
ocfs2-kmp-default
cluster-md-kmp-default-debuginfo
dlm-kmp-default
gfs2-kmp-default-debuginfo
gfs2-kmp-default
kernel-default-debugsource
dlm-kmp-default-debuginfo
ocfs2-kmp-default-debuginfo
kernel-default-debuginfo
cluster-md-kmp-default
kernel-default-livepatch
kernel-64kb-debugsource
kernel-default-extra
kernel-default-extra-debuginfo
kernel-default-livepatch-devel
kernel-azure-devel
kernel-azure-devel-debuginfo
kernel-azure-debuginfo
kernel-azure-debugsource
kernel-azure
reiserfs-kmp-default
reiserfs-kmp-default-debuginfo
kernel-obs-build-debugsource
kernel-obs-build
kernel-syms
kernel-docs
kernel-zfcpdump-debugsource
kernel-zfcpdump-debuginfo
kernel-zfcpdump
kernel-macros
kernel-default-devel
kernel-default-devel-debuginfo
kernel-64kb-debuginfo
kernel-64kb-devel
kernel-64kb-devel-debuginfo
kernel-default-base
linux-hwe-6.8 (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-azure (Ubuntu package)
linux-raspi-realtime (Ubuntu package)
linux-hwe-6.17 (Ubuntu package)
linux-azure-fde-6.17 (Ubuntu package)
linux-azure-6.17 (Ubuntu package)
linux-nvidia-6.17 (Ubuntu package)
linux-oem-6.17 (Ubuntu package)

How to mitigate CVE-2026-31668

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-livepatch-6_4_0-150700_7_54-rt - update to 1-150700.1.3.1
kernel-livepatch-SLE15-SP7-RT_Update_15-debugsource - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_54-rt-debuginfo - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_53_55-default-debuginfo - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_55-default - update to 1-150700.15.3.1
kernel-livepatch-SLE15-SP7_Update_15-debugsource - update to 1-150700.15.3.1
kernel-tools-devel - update to 5.10.0-316.0.0.219
python3-perf-debuginfo - update to 5.10.0-316.0.0.219
python3-perf - update to 5.10.0-316.0.0.219
perf-debuginfo - update to 5.10.0-316.0.0.219
perf - update to 5.10.0-316.0.0.219
kernel-tools-debuginfo - update to 5.10.0-316.0.0.219
kernel-tools - update to 5.10.0-316.0.0.219
kernel-source - update to 5.10.0-316.0.0.219
kernel-headers - update to 5.10.0-316.0.0.219
kernel-devel - update to 5.10.0-316.0.0.219
kernel-debugsource - update to 5.10.0-316.0.0.219
kernel-debuginfo - update to 5.10.0-316.0.0.219
bpftool-debuginfo - update to 5.10.0-316.0.0.219
bpftool - update to 5.10.0-316.0.0.219
kernel - update to 5.10.0-316.0.0.219
linux (Ubuntu package) - addressed in versions 5.15.0.183.154, 5.15.0-183.193, 5.15.0-183.193~20.04.1, 5.15.0.185.108, 5.15.0.185.166, 5.15.0-185.195+fips1, 5.15.0-185.195~20.04.1, 5.15.0-1052.52, 5.15.0.1052.54, 5.15.0-1063.63, 5.15.0-1063.63~20.04.1, 5.15.0.1094.93, 5.15.0-1094.102, 5.15.0.1103.99, 5.15.0-1103.105, 5.15.0.1103.107, 5.15.0-1103.108, 5.15.0.1105.102, 5.15.0.1105.109, 5.15.0-1105.109~20.04.1, 5.15.0.1106.105, 5.15.0.1106.106, 5.15.0-1106.107, 5.15.0-1106.112, 5.15.0.1107.106, 5.15.0-1107.113, 5.15.0.1108.104, 5.15.0-1108.114, 5.15.0.1110.114, 5.15.0-1110.119, 5.15.0.1111.101, 5.15.0.1111.107, 5.15.0.1111.108, 5.15.0.1111.114, 5.15.0-1111.118, 5.15.0-1111.118+fips1, 5.15.0-1111.118~20.04.1, 5.15.0-1111.121, 5.15.0-1111.121+fips1, 5.15.0.1116.114, 5.15.0-1116.125, 5.15.0-1116.125~20.04.1, 6.8.0-134.134, 6.8.0-1057.58~22.04.1, 6.8.0-1058.61+fips1, 6.8.0-1058.61~22.04.1, 6.8.0-1060.61, 6.8.0-1060.63+fips1, 6.8.0-1060.63~22.04.1, 6.8.0-1063.69, 6.8.0-1063.69+fips1, 6.8.1-1055.56, 6.8.1-1055.56~22.04.1, 6.17.0-40.40
linux-xilinx-zynqmp (Ubuntu package) - addressed in versions 5.15.0.1074.77, 5.15.0-1074.78
linux-raspi (Ubuntu package) - addressed in versions 5.15.0.1105.103, 5.15.0-1105.108, 6.8.0-1060.64, 6.17.0-1021.21
linux-gcp-5.15 (Ubuntu package) - addressed in versions 5.15.0-1106.112~20.04.1, 5.15.0-1111.121~20.04.1
linux-oracle-5.15 (Ubuntu package) - update to 5.15.0-1108.114~20.04.1
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0.1116.101, 5.15.0-1116.125+fips1, 6.8.0-134.134+fips1, 6.8.0-1062.69+fips1
linux (Debian package) - addressed in versions 6.1.170-1, 6.12.85-1
dlm-kmp-rt - update to 6.4.0-150700.7.54.1
kernel-rt - update to 6.4.0-150700.7.54.1
kernel-source-rt - update to 6.4.0-150700.7.54.1
kernel-devel-rt - update to 6.4.0-150700.7.54.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.54.1
cluster-md-kmp-rt - update to 6.4.0-150700.7.54.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.54.1
kernel-syms-rt - update to 6.4.0-150700.7.54.1
gfs2-kmp-rt - update to 6.4.0-150700.7.54.1
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.54.1
kernel-rt-debuginfo - update to 6.4.0-150700.7.54.1
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.54.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.54.1
kernel-rt-devel - update to 6.4.0-150700.7.54.1
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.54.1
kernel-rt-debugsource - update to 6.4.0-150700.7.54.1
kernel-64kb - update to 6.4.0-150700.53.55.1
kernel-default - update to 6.4.0-150700.53.55.1
ocfs2-kmp-default - update to 6.4.0-150700.53.55.1
cluster-md-kmp-default-debuginfo - update to 6.4.0-150700.53.55.1
dlm-kmp-default - update to 6.4.0-150700.53.55.1
gfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.55.1
gfs2-kmp-default - update to 6.4.0-150700.53.55.1
kernel-default-debugsource - update to 6.4.0-150700.53.55.1
dlm-kmp-default-debuginfo - update to 6.4.0-150700.53.55.1
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.55.1
kernel-default-debuginfo - update to 6.4.0-150700.53.55.1
cluster-md-kmp-default - update to 6.4.0-150700.53.55.1
kernel-default-livepatch - update to 6.4.0-150700.53.55.1
kernel-64kb-debugsource - update to 6.4.0-150700.53.55.1
kernel-default-extra - update to 6.4.0-150700.53.55.1
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.55.1
kernel-default-livepatch-devel - update to 6.4.0-150700.53.55.1
kernel-azure-devel - update to 6.4.0-150700.53.55.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.55.1
kernel-azure-debuginfo - update to 6.4.0-150700.53.55.1
kernel-azure-debugsource - update to 6.4.0-150700.53.55.1
kernel-azure - update to 6.4.0-150700.53.55.1
reiserfs-kmp-default - update to 6.4.0-150700.53.55.1
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.55.1
kernel-source - update to 6.4.0-150700.53.55.1
kernel-obs-build-debugsource - update to 6.4.0-150700.53.55.1
kernel-obs-build - update to 6.4.0-150700.53.55.1
kernel-syms - update to 6.4.0-150700.53.55.1
kernel-docs - update to 6.4.0-150700.53.55.1
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.55.1
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.55.1
kernel-zfcpdump - update to 6.4.0-150700.53.55.1
kernel-macros - update to 6.4.0-150700.53.55.1
kernel-devel - update to 6.4.0-150700.53.55.1
kernel-default-devel - update to 6.4.0-150700.53.55.1
kernel-default-devel-debuginfo - update to 6.4.0-150700.53.55.1
kernel-64kb-debuginfo - update to 6.4.0-150700.53.55.1
kernel-64kb-devel - update to 6.4.0-150700.53.55.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.55.1
kernel-default-base - update to 6.4.0-150700.53.55.1.150700.17.33.1
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1029.30
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1045.48, 6.8.0-1057.58~22.04.1, 6.8.0-1058.61.1, 6.8.0-1058.64, 6.8.0-1060.61~22.04.1, 6.8.0-1060.63~22.04.1, 6.8.0-1063.69~22.04.1
linux-azure-fde (Ubuntu package) - update to 6.8.0-1062.69
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1063.71, 6.8.0-1063.71~22.04.1
linux-raspi-realtime (Ubuntu package) - update to 6.8.0-2049.50
linux-hwe-6.17 (Ubuntu package) - update to 6.17.0-40.40~24.04.1
linux-azure-fde-6.17 (Ubuntu package) - update to 6.17.0-1018.18~24.04.1
linux-azure-6.17 (Ubuntu package) - update to 6.17.0-1021.21~24.04.1
linux-nvidia-6.17 (Ubuntu package) - update to 6.17.0-1026.26
linux-oem-6.17 (Ubuntu package) - update to 6.17.0-1028.28

External References

Related Security Bulletins