Use-after-free in Linux kernel - CVE-2026-31680

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Main Vulnerability Database Vulnerabilities #VU127873

Use-after-free in Linux kernel - CVE-2026-31680

Published: April 25, 2026


Vulnerability identifier: #VU127873
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-31680
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in ip6fl_seq_show() when reading /proc/net/ip6_flowlabel concurrently with flowlabel release. A local user can trigger concurrent access to dereference freed option state and cause a denial of service.

The issue occurs because the flowlabel remains reachable through the global hash table under RCU after its option state has been freed.


Affected software

Linux kernel
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 12 SP5
Debian Linux
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Micro
SUSE Linux Micro Extras
SUSE Linux Enterprise Live Patching
Basesystem Module
Development Tools Module
SUSE Real Time Module
Legacy Module
Public Cloud Module
Ubuntu
openEuler
kgraft-patch-4_12_14-122_320-default
kernel-livepatch-6_4_0-150700_7_62-rt-debuginfo
kernel-livepatch-SLE15-SP7-RT_Update_17-debugsource
kernel-livepatch-6_4_0-150700_7_62-rt
kernel-livepatch-SLE15-SP7_Update_17-debugsource
kernel-livepatch-6_4_0-150700_53_63-default
kernel-livepatch-6_4_0-150700_53_63-default-debuginfo
gfs2-kmp-default-debuginfo
kernel-default
kernel-macros
kernel-devel
kernel-default-man
kernel-source
kernel-default-devel
kernel-default-base
kernel-default-kgraft
kernel-default-debugsource
kernel-default-base-debuginfo
kernel-default-devel-debuginfo
cluster-md-kmp-default-debuginfo
cluster-md-kmp-default
kernel-syms
ocfs2-kmp-default-debuginfo
gfs2-kmp-default
ocfs2-kmp-default
dlm-kmp-default-debuginfo
kernel-default-debuginfo
dlm-kmp-default
kernel-default-kgraft-devel
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
bpftool
kernel
kernel-headers
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-intel-iot-realtime (Ubuntu package)
linux-ibm-5.15 (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-azure (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux (Debian package)
kernel-obs-build
kernel-64kb-debugsource
kernel-64kb-devel
kernel-kvmsmall
kernel-default-livepatch
kernel-kvmsmall-debugsource
kernel-kvmsmall-debuginfo
kernel-obs-build-debugsource
kernel-64kb
kernel-source-rt
kernel-devel-rt
cluster-md-kmp-rt-debuginfo
kernel-rt
dlm-kmp-rt
gfs2-kmp-rt-debuginfo
kernel-rt-debuginfo
dlm-kmp-rt-debuginfo
gfs2-kmp-rt
ocfs2-kmp-rt
kernel-rt-devel-debuginfo
kernel-rt-devel
kernel-rt-debugsource
kernel-syms-rt
cluster-md-kmp-rt
ocfs2-kmp-rt-debuginfo
kernel-zfcpdump-debuginfo
kernel-zfcpdump-debugsource
kernel-default-livepatch-devel
kernel-docs
kernel-default-extra-debuginfo
kernel-default-extra
kernel-azure
kernel-azure-debugsource
kernel-azure-devel
kernel-64kb-debuginfo
kernel-64kb-devel-debuginfo
kernel-zfcpdump
reiserfs-kmp-default
reiserfs-kmp-default-debuginfo
kernel-azure-devel-debuginfo
kernel-azure-debuginfo
kernel-extra-modules
linux-fips (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle-6.8 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-gcp-fips (Ubuntu package)

How to mitigate CVE-2026-31680

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kgraft-patch-4_12_14-122_320-default - update to 1-8.3.1
kernel-livepatch-6_4_0-150700_7_62-rt-debuginfo - update to 1-150700.1.3.1
kernel-livepatch-SLE15-SP7-RT_Update_17-debugsource - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_62-rt - update to 1-150700.1.3.1
kernel-livepatch-SLE15-SP7_Update_17-debugsource - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_63-default - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_63-default-debuginfo - update to 1-150700.15.3.1
gfs2-kmp-default-debuginfo - addressed in versions 4.12.14-122.320.1, 6.4.0-150700.53.63.1
kernel-default - addressed in versions 4.12.14-122.320.1, 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-macros - addressed in versions 4.12.14-122.320.1, 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-devel - addressed in versions 4.12.14-122.320.1, 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-default-man - update to 4.12.14-122.320.1
kernel-source - addressed in versions 4.12.14-122.320.1, 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-default-devel - addressed in versions 4.12.14-122.320.1, 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-default-base - addressed in versions 4.12.14-122.320.1, 6.4.0-48.1.21.25, 6.4.0-150700.53.63.1.150700.17.37.1
kernel-default-kgraft - update to 4.12.14-122.320.1
kernel-default-debugsource - addressed in versions 4.12.14-122.320.1, 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-default-base-debuginfo - update to 4.12.14-122.320.1
kernel-default-devel-debuginfo - addressed in versions 4.12.14-122.320.1, 6.4.0-48.1, 6.4.0-150700.53.63.1
cluster-md-kmp-default-debuginfo - addressed in versions 4.12.14-122.320.1, 6.4.0-150700.53.63.1
cluster-md-kmp-default - addressed in versions 4.12.14-122.320.1, 6.4.0-150700.53.63.1
kernel-syms - addressed in versions 4.12.14-122.320.1, 6.4.0-48.1, 6.4.0-150700.53.63.1
ocfs2-kmp-default-debuginfo - addressed in versions 4.12.14-122.320.1, 6.4.0-150700.53.63.1
gfs2-kmp-default - addressed in versions 4.12.14-122.320.1, 6.4.0-150700.53.63.1
ocfs2-kmp-default - addressed in versions 4.12.14-122.320.1, 6.4.0-150700.53.63.1
dlm-kmp-default-debuginfo - addressed in versions 4.12.14-122.320.1, 6.4.0-150700.53.63.1
kernel-default-debuginfo - addressed in versions 4.12.14-122.320.1, 6.4.0-48.1, 6.4.0-150700.53.63.1
dlm-kmp-default - addressed in versions 4.12.14-122.320.1, 6.4.0-150700.53.63.1
kernel-default-kgraft-devel - update to 4.12.14-122.320.1
python3-perf-debuginfo - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
python3-perf - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
perf-debuginfo - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
perf - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
kernel-tools-devel - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
kernel-tools-debuginfo - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
kernel-tools - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
kernel-source - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
kernel-devel - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
kernel-debugsource - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
kernel-debuginfo - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
bpftool-debuginfo - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
bpftool - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
kernel - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
kernel-headers - addressed in versions 5.10.0-313.0.0.216, 6.6.0-145.0.9.136, 6.6.0-145.0.9.140, 6.6.0-145.0.9.148
linux (Ubuntu package) - addressed in versions 5.15.0.184.155, 5.15.0-184.194, 5.15.0-184.194~20.04.1, 5.15.0.186.166, 5.15.0-186.196, 5.15.0-186.196~20.04.1, 5.15.0.1075.78, 5.15.0-1075.79, 5.15.0.1095.94, 5.15.0-1095.103, 5.15.0.1104.100, 5.15.0-1104.109, 5.15.0.1108.107, 5.15.0-1108.114, 5.15.0.1111.115, 5.15.0-1111.120+fips1, 5.15.0.1112.102, 5.15.0.1112.109, 5.15.0-1112.122, 5.15.0-1112.122+fips1, 6.8.0-136.136, 6.8.0-1046.50, 6.8.0-1059.67, 6.8.0-1064.72, 6.8.0-1064.72~22.04.1, 6.8.1-1056.57, 6.8.1-1056.57~22.04.2
linux-aws (Ubuntu package) - addressed in versions 5.15.0.186.109, 5.15.0-186.196+fips1, 5.15.0.1106.103, 5.15.0-1106.110, 5.15.0.1107.107, 5.15.0-1107.108, 5.15.0.1112.108, 5.15.0.1112.115, 5.15.0-1112.119, 5.15.0-1112.119+fips1, 5.15.0-1112.119~20.04.1, 6.8.0-1061.64+1
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1053.53, 5.15.0.1053.55, 5.15.0.1064.64, 5.15.0-1064.66
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1064.66~20.04.1
linux-intel-iot-realtime (Ubuntu package) - addressed in versions 5.15.0-1104.106, 5.15.0.1104.108, 5.15.0-1107.113~20.04.1
linux-ibm-5.15 (Ubuntu package) - update to 5.15.0-1106.110~20.04.1
linux-intel-iotg (Ubuntu package) - addressed in versions 5.15.0.1107.106, 5.15.0-1107.113
linux-azure (Ubuntu package) - addressed in versions 5.15.0.1109.105, 5.15.0-1109.115, 5.15.0.1117.115, 5.15.0-1117.126, 6.8.0-1063.71, 6.8.0-1063.71~22.04.1
linux-azure-5.15 (Ubuntu package) - addressed in versions 5.15.0-1109.115~20.04.1, 5.15.0-1117.126~20.04.1, 5.15.0-1117.126~20.04.2
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0.1117.102, 5.15.0-1117.126+fips1, 6.8.0-1063.71+fips2
linux-azure-fde (Ubuntu package) - addressed in versions 5.15.0-1117.126, 6.8.0-1062.69
linux (Debian package) - addressed in versions 6.1.170-1, 6.12.85-1
kernel-obs-build - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-64kb-debugsource - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-64kb-devel - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-kvmsmall - update to 6.4.0-48.1
kernel-default-livepatch - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-kvmsmall-debugsource - update to 6.4.0-48.1
kernel-kvmsmall-debuginfo - update to 6.4.0-48.1
kernel-obs-build-debugsource - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-64kb - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-source-rt - update to 6.4.0-150700.7.62.1
kernel-devel-rt - update to 6.4.0-150700.7.62.1
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.62.1
kernel-rt - update to 6.4.0-150700.7.62.1
dlm-kmp-rt - update to 6.4.0-150700.7.62.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.62.1
kernel-rt-debuginfo - update to 6.4.0-150700.7.62.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.62.1
gfs2-kmp-rt - update to 6.4.0-150700.7.62.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.62.1
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.62.1
kernel-rt-devel - update to 6.4.0-150700.7.62.1
kernel-rt-debugsource - update to 6.4.0-150700.7.62.1
kernel-syms-rt - update to 6.4.0-150700.7.62.1
cluster-md-kmp-rt - update to 6.4.0-150700.7.62.1
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.62.1
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.63.1
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.63.1
kernel-default-livepatch-devel - update to 6.4.0-150700.53.63.1
kernel-docs - update to 6.4.0-150700.53.63.1
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.63.1
kernel-default-extra - update to 6.4.0-150700.53.63.1
kernel-azure - update to 6.4.0-150700.53.63.1
kernel-azure-debugsource - update to 6.4.0-150700.53.63.1
kernel-azure-devel - update to 6.4.0-150700.53.63.1
kernel-64kb-debuginfo - update to 6.4.0-150700.53.63.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.63.1
kernel-zfcpdump - update to 6.4.0-150700.53.63.1
reiserfs-kmp-default - update to 6.4.0-150700.53.63.1
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.63.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.63.1
kernel-azure-debuginfo - update to 6.4.0-150700.53.63.1
kernel-extra-modules - update to 6.6.0-145.0.9.140
linux-fips (Ubuntu package) - addressed in versions 6.8.0-136.136+fips2, 6.8.0-136.136.2, 6.8.0-136.136.2~22.04.1, 6.8.0-1058.61
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1030.31, 6.8.0-1033.34, 6.8.0-1061.62, 6.8.0-1061.62~22.04.1
linux-oracle-6.8 (Ubuntu package) - update to 6.8.0-1058.61~22.04.1
linux-nvidia (Ubuntu package) - addressed in versions 6.8.0-1059.62, 6.8.0-1059.62.1, 6.8.0-1059.62~22.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1061.64+fips1, 6.8.0-1061.64~22.04.1
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1064.72+fips1

External References

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