Use-after-free in Linux kernel - CVE-2026-31657

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Main Vulnerability Database Vulnerabilities #VU127735

Use-after-free in Linux kernel - CVE-2026-31657

Published: April 25, 2026


Vulnerability identifier: #VU127735
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-2026-31657
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 the batman-adv BLA claim handling code when processing netlink claim dump operations or checking claims. A local user can trigger concurrent claim updates and reader access to dereference a freed backbone gateway pointer to cause a denial of service.


Affected software

Linux kernel
Debian Linux
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Desktop 15
Ubuntu
Development Tools Module
Basesystem Module
SUSE Real Time Module
Legacy Module
Public Cloud Module
SUSE Linux Enterprise Live Patching
linux (Ubuntu package)
linux-kvm (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-azure (Ubuntu package)
linux-raspi (Ubuntu package)
linux-oracle (Ubuntu package)
linux-lowlatency (Ubuntu package)
linux-gke (Ubuntu package)
linux-aws-5.15 (Ubuntu package)
linux-lowlatency-hwe-5.15 (Ubuntu package)
linux-hwe-5.15 (Ubuntu package)
linux-fips (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-tegra-igx (Ubuntu package)
linux-realtime (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-azure-fde-5.15 (Ubuntu package)
linux-gkeop (Ubuntu package)
linux-ibm-5.15 (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-ibm (Ubuntu package)
linux-intel-iotg-5.15 (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-xilinx-zynqmp (Ubuntu package)
linux-intel-iot-realtime (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux-aws-fips (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-hwe-6.17 (Ubuntu package)
linux-gcp-6.17 (Ubuntu package)
linux-oracle-6.17 (Ubuntu package)
linux-azure-6.17 (Ubuntu package)
linux-oem-6.17 (Ubuntu package)
linux-nvidia-6.17 (Ubuntu package)
linux-aws-6.17 (Ubuntu package)
linux-realtime-6.17 (Ubuntu package)
kernel-livepatch-SLE15-SP7-RT_Update_18-debugsource
kernel-livepatch-6_4_0-150700_7_67-rt
kernel-livepatch-6_4_0-150700_7_67-rt-debuginfo
kernel-livepatch-SLE15-SP7_Update_19-debugsource
kernel-livepatch-6_4_0-150700_53_73-default-debuginfo
kernel-livepatch-6_4_0-150700_53_73-default
kernel-rt-devel-debuginfo
kernel-rt
kernel-source-rt
kernel-devel-rt
kernel-rt-debuginfo
dlm-kmp-rt
cluster-md-kmp-rt
ocfs2-kmp-rt
gfs2-kmp-rt
dlm-kmp-rt-debuginfo
kernel-rt-devel
gfs2-kmp-rt-debuginfo
cluster-md-kmp-rt-debuginfo
kernel-syms-rt
ocfs2-kmp-rt-debuginfo
kernel-rt-debugsource
kernel-syms
kernel-source
kernel-docs
kernel-macros
kernel-devel
kernel-64kb-devel
cluster-md-kmp-default-debuginfo
dlm-kmp-default-debuginfo
ocfs2-kmp-default
kernel-zfcpdump
kernel-zfcpdump-debuginfo
kernel-zfcpdump-debugsource
kernel-default
kernel-64kb-debuginfo
kernel-64kb-devel-debuginfo
dlm-kmp-default
kernel-64kb-debugsource
kernel-64kb
kernel-default-devel-debuginfo
kernel-default-devel
kernel-default-debuginfo
kernel-default-debugsource
reiserfs-kmp-default-debuginfo
kernel-azure
kernel-default-livepatch
kernel-azure-debuginfo
kernel-default-livepatch-devel
kernel-azure-devel-debuginfo
kernel-azure-devel
kernel-default-extra
kernel-default-extra-debuginfo
reiserfs-kmp-default
kernel-obs-build-debugsource
kernel-obs-build
ocfs2-kmp-default-debuginfo
gfs2-kmp-default-debuginfo
gfs2-kmp-default
cluster-md-kmp-default
kernel-azure-debugsource
kernel-default-base
linux-aws-hwe (Ubuntu package)
linux-oracle-5.4 (Ubuntu package)
linux-azure-5.4 (Ubuntu package)
linux (Debian package)
linux-hwe-6.8 (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-raspi-realtime (Ubuntu package)
linux-azure-fde-6.17 (Ubuntu package)

How to mitigate CVE-2026-31657

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 4.15.0-254.266, 4.15.0-1150.162, 4.15.0-1177.182, 4.15.0-1188.205, 4.15.0-1195.208, 4.15.0-1205.220, 4.15.0-2096.102, 4.15.0-2113.119, 4.15.0-2133.139, 4.15.0.254.238, 4.15.0.1150.147, 4.15.0.1177.168, 4.15.0.1188.201~16.04.1, 4.15.0.1195.193, 4.15.0.1205.173, 4.15.0.2096.94, 4.15.0.2113.109, 4.15.0.2133.127, 5.4.0-234.254~18.04.1, 5.4.0-234.254, 5.4.0-1066.69, 5.4.0-1080.84, 5.4.0-1108.113~18.04.1, 5.4.0-1108.113, 5.4.0-1121.128, 5.4.0-1136.146, 5.4.0-1145.158~18.04.1, 5.4.0-1145.158, 5.4.0-1160.170+fips1, 5.4.0-1162.173~18.04.1, 5.4.0-1162.173, 5.4.0-1165.174~18.04.1, 5.4.0-1165.174, 5.4.0-1167.173, 5.4.0.234.226, 5.4.0.1080.80, 5.4.0.1108.137, 5.4.0.1121.117, 5.4.0.1136.133, 5.4.0.1145.176, 5.4.0.1160.154, 5.4.0.1162.160, 5.4.0.1165.167, 5.4.0.1167.159, 5.15.0-185.195, 6.8.0-134.134, 6.8.0-1057.58~22.04.1, 6.8.0-1058.61~22.04.1, 6.8.0-1058.61+fips1, 6.8.0-1060.61, 6.8.0-1060.63~22.04.1, 6.8.0-1060.63+fips1, 6.8.0-1063.69, 6.8.0-1063.69+fips1, 6.8.1-1055.56~22.04.1, 6.8.1-1055.56, 6.17.0-40.40
linux-kvm (Ubuntu package) - addressed in versions 5.4.0-1149.158, 5.4.0.1149.145, 5.15.0-1103.108
linux-aws (Ubuntu package) - addressed in versions 5.15.0-1111.118, 6.17.0-1019.19
linux-gcp (Ubuntu package) - addressed in versions 5.15.0-1111.121, 6.17.0-1020.22
linux-azure (Ubuntu package) - addressed in versions 4.15.0-1205.220~14.04.1, 5.15.0-1116.125, 6.8.0-1063.71~22.04.1, 6.8.0-1063.71
linux-raspi (Ubuntu package) - addressed in versions 5.15.0-1105.108, 6.8.0-1060.64, 6.17.0-1021.21
linux-oracle (Ubuntu package) - addressed in versions 4.15.0-1158.169~16.04.1, 4.15.0-1158.169, 4.15.0.1158.163, 5.15.0-1108.114, 6.17.0-1018.18
linux-lowlatency (Ubuntu package) - update to 5.15.0-183.193
linux-gke (Ubuntu package) - update to 5.15.0-1107.113
linux-aws-5.15 (Ubuntu package) - update to 5.15.0-1111.118~20.04.1
linux-lowlatency-hwe-5.15 (Ubuntu package) - update to 5.15.0-183.193~20.04.1
linux-hwe-5.15 (Ubuntu package) - update to 5.15.0-185.195~20.04.1
linux-fips (Ubuntu package) - update to 5.15.0-185.195+fips1
linux-azure-5.15 (Ubuntu package) - update to 5.15.0-1116.125~20.04.1
linux-nvidia (Ubuntu package) - update to 5.15.0-1106.107
linux-nvidia-tegra-igx (Ubuntu package) - update to 5.15.0-1052.52
linux-realtime (Ubuntu package) - addressed in versions 5.15.0-1110.119, 6.17.0-1017.19
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1063.63, 6.8.0-1029.30
linux-azure-fde-5.15 (Ubuntu package) - update to 5.15.0-1116.125~20.04.1
linux-gkeop (Ubuntu package) - update to 5.15.0-1094.102
linux-ibm-5.15 (Ubuntu package) - update to 5.15.0-1105.109~20.04.1
linux-intel-iotg (Ubuntu package) - update to 5.15.0-1106.112
linux-ibm (Ubuntu package) - update to 5.15.0-1105.109
linux-intel-iotg-5.15 (Ubuntu package) - update to 5.15.0-1106.112~20.04.1
linux-oracle-5.15 (Ubuntu package) - update to 5.15.0-1108.114~20.04.1
linux-gcp-5.15 (Ubuntu package) - update to 5.15.0-1111.121~20.04.1
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1063.63~20.04.1
linux-xilinx-zynqmp (Ubuntu package) - update to 5.15.0-1074.78
linux-intel-iot-realtime (Ubuntu package) - update to 5.15.0-1103.105
linux-gcp-fips (Ubuntu package) - addressed in versions 5.4.0-1165.174+fips1, 5.4.0.1165.107, 5.15.0-1111.121+fips1
linux-aws-fips (Ubuntu package) - addressed in versions 5.4.0-1163.174+fips1, 5.4.0.1163.110, 5.15.0-1111.118+fips1
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0-1116.125+fips1, 6.8.0-134.134+fips1, 6.8.0-1062.69+fips1
linux-hwe-6.17 (Ubuntu package) - update to 6.17.0-40.40~24.04.1
linux-gcp-6.17 (Ubuntu package) - update to 6.17.0-1020.22~24.04.1
linux-oracle-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-oem-6.17 (Ubuntu package) - update to 6.17.0-1028.28
linux-nvidia-6.17 (Ubuntu package) - update to 6.17.0-1026.26
linux-aws-6.17 (Ubuntu package) - update to 6.17.0-1019.19~24.04.1
linux-realtime-6.17 (Ubuntu package) - update to 6.17.0-1017.19~24.04.1
kernel-livepatch-SLE15-SP7-RT_Update_18-debugsource - update to 1-150700.1.5.1
kernel-livepatch-6_4_0-150700_7_67-rt - update to 1-150700.1.5.1
kernel-livepatch-6_4_0-150700_7_67-rt-debuginfo - update to 1-150700.1.5.1
kernel-livepatch-SLE15-SP7_Update_19-debugsource - update to 1-150700.15.3.4
kernel-livepatch-6_4_0-150700_53_73-default-debuginfo - update to 1-150700.15.3.4
kernel-livepatch-6_4_0-150700_53_73-default - update to 1-150700.15.3.4
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.67.1
kernel-rt - update to 6.4.0-150700.7.67.1
kernel-source-rt - update to 6.4.0-150700.7.67.1
kernel-devel-rt - update to 6.4.0-150700.7.67.1
kernel-rt-debuginfo - update to 6.4.0-150700.7.67.1
dlm-kmp-rt - update to 6.4.0-150700.7.67.1
cluster-md-kmp-rt - update to 6.4.0-150700.7.67.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.67.1
gfs2-kmp-rt - update to 6.4.0-150700.7.67.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-rt-devel - update to 6.4.0-150700.7.67.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-syms-rt - update to 6.4.0-150700.7.67.1
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-rt-debugsource - update to 6.4.0-150700.7.67.1
kernel-syms - update to 6.4.0-150700.53.73.1
kernel-source - update to 6.4.0-150700.53.73.1
kernel-docs - update to 6.4.0-150700.53.73.1
kernel-macros - update to 6.4.0-150700.53.73.1
kernel-devel - update to 6.4.0-150700.53.73.1
kernel-64kb-devel - update to 6.4.0-150700.53.73.2
cluster-md-kmp-default-debuginfo - update to 6.4.0-150700.53.73.2
dlm-kmp-default-debuginfo - update to 6.4.0-150700.53.73.2
ocfs2-kmp-default - update to 6.4.0-150700.53.73.2
kernel-zfcpdump - update to 6.4.0-150700.53.73.2
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.73.2
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.73.2
kernel-default - update to 6.4.0-150700.53.73.2
kernel-64kb-debuginfo - update to 6.4.0-150700.53.73.2
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.73.2
dlm-kmp-default - update to 6.4.0-150700.53.73.2
kernel-64kb-debugsource - update to 6.4.0-150700.53.73.2
kernel-64kb - update to 6.4.0-150700.53.73.2
kernel-default-devel-debuginfo - update to 6.4.0-150700.53.73.2
kernel-default-devel - update to 6.4.0-150700.53.73.2
kernel-default-debuginfo - update to 6.4.0-150700.53.73.2
kernel-default-debugsource - update to 6.4.0-150700.53.73.2
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.73.2
kernel-azure - update to 6.4.0-150700.53.73.2
kernel-default-livepatch - update to 6.4.0-150700.53.73.2
kernel-azure-debuginfo - update to 6.4.0-150700.53.73.2
kernel-default-livepatch-devel - update to 6.4.0-150700.53.73.2
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.73.2
kernel-azure-devel - update to 6.4.0-150700.53.73.2
kernel-default-extra - update to 6.4.0-150700.53.73.2
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.73.2
reiserfs-kmp-default - update to 6.4.0-150700.53.73.2
kernel-obs-build-debugsource - update to 6.4.0-150700.53.73.2
kernel-obs-build - update to 6.4.0-150700.53.73.2
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.73.2
gfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.73.2
gfs2-kmp-default - update to 6.4.0-150700.53.73.2
cluster-md-kmp-default - update to 6.4.0-150700.53.73.2
kernel-azure-debugsource - update to 6.4.0-150700.53.73.2
kernel-default-base - update to 6.4.0-150700.53.73.2.150700.17.41.4
linux-aws-hwe (Ubuntu package) - addressed in versions 4.15.0-254.266~16.04.1, 4.15.0-1188.205~16.04.1, 4.15.0-1195.208~16.04.1, 4.15.0-1205.220~16.04.1
linux-oracle-5.4 (Ubuntu package) - update to 5.4.0-1161.171~18.04.1
linux-azure-5.4 (Ubuntu package) - addressed in versions 5.4.0-1167.173~18.04.1, 5.4.0-1167.173+fips1, 5.4.0.1167.103
linux (Debian package) - addressed in versions 6.1.170-1, 6.12.85-1
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
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-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-azure-fde (Ubuntu package) - update to 6.8.0-1062.69
linux-raspi-realtime (Ubuntu package) - update to 6.8.0-2049.50
linux-azure-fde-6.17 (Ubuntu package) - update to 6.17.0-1018.18~24.04.1

External References

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