Improper access control in Linux kernel - CVE-2026-31503

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Main Vulnerability Database Vulnerabilities #VU127649

Improper access control in Linux kernel - CVE-2026-31503

Published: April 24, 2026


Vulnerability identifier: #VU127649
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-2026-31503
CWE-ID: CWE-284
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 improper access control in the UDP socket bind conflict check when binding a wildcard address after multiple sockets are already bound to the same local port. A local user can bind sockets to multiple specific local addresses on the same port and then bind a wildcard address to bypass conflict detection and cause a denial of service.

The issue affects IPv6 wildcard, IPv4 wildcard, and IPv4-mapped wildcard addresses when the bind bucket count exceeds 10.


Affected software

Linux kernel
Debian Linux
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Desktop 15
SUSE Real Time Module
Basesystem Module
Development Tools Module
Legacy Module
Public Cloud Module
SUSE Linux Enterprise Live Patching
Ubuntu
openEuler
kernel-livepatch-6_4_0-150700_7_67-rt
kernel-livepatch-SLE15-SP7-RT_Update_18-debugsource
kernel-livepatch-6_4_0-150700_7_67-rt-debuginfo
kernel-livepatch-6_4_0-150700_53_73-default-debuginfo
kernel-livepatch-6_4_0-150700_53_73-default
kernel-livepatch-SLE15-SP7_Update_19-debugsource
linux (Debian package)
kernel-rt-devel-debuginfo
kernel-source-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
cluster-md-kmp-rt
dlm-kmp-rt
kernel-rt-debuginfo
kernel-devel-rt
kernel-rt
kernel-macros
kernel-syms
kernel-docs
kernel-source
kernel-devel
ocfs2-kmp-default
kernel-obs-build-debugsource
kernel-obs-build
kernel-default-devel-debuginfo
kernel-default-devel
ocfs2-kmp-default-debuginfo
gfs2-kmp-default-debuginfo
gfs2-kmp-default
cluster-md-kmp-default
dlm-kmp-default
cluster-md-kmp-default-debuginfo
dlm-kmp-default-debuginfo
kernel-default-debugsource
kernel-zfcpdump
kernel-zfcpdump-debuginfo
kernel-zfcpdump-debugsource
kernel-default
kernel-64kb-debuginfo
kernel-64kb-devel-debuginfo
kernel-64kb-devel
kernel-64kb-debugsource
kernel-64kb
kernel-default-debuginfo
reiserfs-kmp-default
kernel-azure-debugsource
kernel-azure-devel
kernel-azure-devel-debuginfo
kernel-azure-debuginfo
kernel-azure
kernel-default-livepatch
kernel-default-livepatch-devel
kernel-default-extra
kernel-default-extra-debuginfo
reiserfs-kmp-default-debuginfo
kernel-default-base
kernel-headers
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-extra-modules
linux (Ubuntu package)
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-aws (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-azure (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-gcp-fips (Ubuntu package)

How to mitigate CVE-2026-31503

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-livepatch-6_4_0-150700_7_67-rt - update to 1-150700.1.5.1
kernel-livepatch-SLE15-SP7-RT_Update_18-debugsource - update to 1-150700.1.5.1
kernel-livepatch-6_4_0-150700_7_67-rt-debuginfo - update to 1-150700.1.5.1
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-livepatch-SLE15-SP7_Update_19-debugsource - update to 1-150700.15.3.4
linux (Debian package) - addressed in versions 6.1.170-1, 6.12.85-1
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.67.1
kernel-source-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
cluster-md-kmp-rt - update to 6.4.0-150700.7.67.1
dlm-kmp-rt - update to 6.4.0-150700.7.67.1
kernel-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-devel-rt - update to 6.4.0-150700.7.67.1
kernel-rt - update to 6.4.0-150700.7.67.1
kernel-macros - update to 6.4.0-150700.53.73.1
kernel-syms - update to 6.4.0-150700.53.73.1
kernel-docs - update to 6.4.0-150700.53.73.1
kernel-source - update to 6.4.0-150700.53.73.1
kernel-devel - update to 6.4.0-150700.53.73.1
ocfs2-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
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
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
dlm-kmp-default - 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
kernel-default-debugsource - 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
kernel-64kb-devel - 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-debuginfo - update to 6.4.0-150700.53.73.2
reiserfs-kmp-default - update to 6.4.0-150700.53.73.2
kernel-azure-debugsource - update to 6.4.0-150700.53.73.2
kernel-azure-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-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-default-livepatch-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-debuginfo - 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
kernel-headers - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
python3-perf-debuginfo - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
python3-perf - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
perf-debuginfo - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
perf - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
kernel-tools-devel - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
kernel-tools-debuginfo - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
kernel-tools - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
kernel - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
bpftool - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
bpftool-debuginfo - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
kernel-debuginfo - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
kernel-debugsource - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
kernel-devel - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
kernel-source - addressed in versions 6.6.0-145.0.13.139, 6.6.0-145.1.13.151, 6.6.0-145.3.13.143
kernel-extra-modules - update to 6.6.0-145.3.13.143
linux (Ubuntu package) - addressed in versions 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-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-aws (Ubuntu package) - update to 6.8.0-1061.64+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-azure-fips (Ubuntu package) - update to 6.8.0-1063.71+fips2
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1064.72+fips1

External References

Related Security Bulletins