Use of uninitialized resource in Linux kernel - CVE-2026-31664

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Main Vulnerability Database Vulnerabilities #VU127725

Use of uninitialized resource in Linux kernel - CVE-2026-31664

Published: April 25, 2026


Vulnerability identifier: #VU127725
CSH Severity: Low
CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-31664
CWE-ID: CWE-908
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to uninitialized memory exposure in build_polexpire() when sending netlink multicast notifications to XFRMNLGRP_EXPIRE listeners. A local user can receive a crafted expiration notification to disclose sensitive information.

The issue leaks trailing padding bytes from struct xfrm_user_polexpire to userspace.


Affected software

Linux kernel
Debian Linux
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 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
Basesystem Module
SUSE Real Time Module
Development Tools Module
SUSE Linux Enterprise Live Patching
Legacy Module
Public Cloud Module
Ubuntu
openEuler
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-6_4_0-150700_53_63-default-debuginfo
kernel-livepatch-6_4_0-150700_53_63-default
kernel-livepatch-SLE15-SP7_Update_17-debugsource
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-64kb-devel
kernel-default
kernel-64kb
kernel-syms
kernel-default-devel
kernel-default-debugsource
kernel-obs-build-debugsource
kernel-obs-build
kernel-kvmsmall-debuginfo
kernel-kvmsmall-debugsource
kernel-64kb-debugsource
kernel-default-devel-debuginfo
kernel-default-debuginfo
kernel-macros
kernel-devel
kernel-source
kernel-kvmsmall
kernel-default-livepatch
kernel-default-base
kernel-syms-rt
dlm-kmp-rt-debuginfo
kernel-rt-debuginfo
gfs2-kmp-rt
gfs2-kmp-rt-debuginfo
dlm-kmp-rt
kernel-rt
kernel-devel-rt
kernel-source-rt
ocfs2-kmp-rt
kernel-rt-devel-debuginfo
cluster-md-kmp-rt-debuginfo
kernel-rt-devel
kernel-rt-debugsource
cluster-md-kmp-rt
ocfs2-kmp-rt-debuginfo
reiserfs-kmp-default-debuginfo
ocfs2-kmp-default-debuginfo
dlm-kmp-default-debuginfo
gfs2-kmp-default
cluster-md-kmp-default-debuginfo
ocfs2-kmp-default
dlm-kmp-default
gfs2-kmp-default-debuginfo
cluster-md-kmp-default
kernel-default-livepatch-devel
kernel-zfcpdump-debuginfo
reiserfs-kmp-default
kernel-azure-devel-debuginfo
kernel-azure-devel
kernel-azure-debuginfo
kernel-azure-debugsource
kernel-azure
kernel-docs
kernel-default-extra-debuginfo
kernel-default-extra
kernel-zfcpdump
kernel-64kb-debuginfo
kernel-zfcpdump-debugsource
kernel-64kb-devel-debuginfo
kernel-headers
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
bpftool
kernel
perf
perf-debuginfo
python3-perf
python3-perf-debuginfo
kernel-tools
kernel-tools-debuginfo
kernel-tools-devel
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-2026-31664

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
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-6_4_0-150700_53_63-default-debuginfo - 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-SLE15-SP7_Update_17-debugsource - update to 1-150700.15.3.1
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-64kb-devel - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-default - 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-syms - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-default-devel - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-default-debugsource - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-obs-build-debugsource - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-obs-build - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-kvmsmall-debuginfo - update to 6.4.0-48.1
kernel-kvmsmall-debugsource - update to 6.4.0-48.1
kernel-64kb-debugsource - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-default-devel-debuginfo - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-default-debuginfo - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-macros - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-devel - addressed in versions 6.4.0-48.1, 6.4.0-150700.53.63.1
kernel-source - 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-default-base - addressed in versions 6.4.0-48.1.21.25, 6.4.0-150700.53.63.1.150700.17.37.1
kernel-syms-rt - update to 6.4.0-150700.7.62.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.62.1
kernel-rt-debuginfo - update to 6.4.0-150700.7.62.1
gfs2-kmp-rt - update to 6.4.0-150700.7.62.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.62.1
dlm-kmp-rt - update to 6.4.0-150700.7.62.1
kernel-rt - update to 6.4.0-150700.7.62.1
kernel-devel-rt - update to 6.4.0-150700.7.62.1
kernel-source-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
cluster-md-kmp-rt-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
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
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.63.1
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.63.1
dlm-kmp-default-debuginfo - update to 6.4.0-150700.53.63.1
gfs2-kmp-default - update to 6.4.0-150700.53.63.1
cluster-md-kmp-default-debuginfo - update to 6.4.0-150700.53.63.1
ocfs2-kmp-default - update to 6.4.0-150700.53.63.1
dlm-kmp-default - update to 6.4.0-150700.53.63.1
gfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.63.1
cluster-md-kmp-default - update to 6.4.0-150700.53.63.1
kernel-default-livepatch-devel - update to 6.4.0-150700.53.63.1
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.63.1
reiserfs-kmp-default - update to 6.4.0-150700.53.63.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.63.1
kernel-azure-devel - update to 6.4.0-150700.53.63.1
kernel-azure-debuginfo - update to 6.4.0-150700.53.63.1
kernel-azure-debugsource - update to 6.4.0-150700.53.63.1
kernel-azure - 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-zfcpdump - update to 6.4.0-150700.53.63.1
kernel-64kb-debuginfo - update to 6.4.0-150700.53.63.1
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.63.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.63.1
kernel-source - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
kernel-headers - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
kernel-devel - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
kernel-debugsource - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
kernel-debuginfo - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
bpftool-debuginfo - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
bpftool - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
kernel - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
perf - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
perf-debuginfo - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
python3-perf - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
python3-perf-debuginfo - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
kernel-tools - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
kernel-tools-debuginfo - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
kernel-tools-devel - addressed in versions 6.6.0-145.1.19.156, 6.6.0-145.3.17.150
kernel-extra-modules - update to 6.6.0-145.3.17.150
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

Related Security Bulletins