Improper input validation in Linux kernel - CVE-2026-43491

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Main Vulnerability Database Vulnerabilities #VU131909

Improper input validation in Linux kernel - CVE-2026-43491

Published: May 20, 2026


Vulnerability identifier: #VU131909
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-43491
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper input validation in the qrtr namespace service when handling NEW_SERVER messages. A remote attacker can send a flood of NEW_SERVER messages to cause a denial of service.

Exploitation can exhaust memory by registering excessive servers for a node.


Affected software

Linux kernel
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Micro
SUSE Linux Micro Extras
Development Tools Module
SUSE Real Time Module
SUSE Linux Enterprise Live Patching
Public Cloud Module
Legacy Module
Basesystem Module
Ubuntu
kernel-livepatch-6_4_0-150700_7_62-rt
kernel-livepatch-SLE15-SP7-RT_Update_17-debugsource
kernel-livepatch-6_4_0-150700_7_62-rt-debuginfo
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
kernel-default-livepatch
kernel-default
kernel-kvmsmall
kernel-source
kernel-devel
kernel-macros
kernel-default-debugsource
kernel-default-debuginfo
kernel-default-devel-debuginfo
kernel-64kb-devel
kernel-64kb-debugsource
kernel-obs-build
kernel-obs-build-debugsource
kernel-default-devel
kernel-syms
kernel-64kb
kernel-kvmsmall-debugsource
kernel-kvmsmall-debuginfo
kernel-default-base
ocfs2-kmp-rt
kernel-source-rt
kernel-devel-rt
kernel-rt
dlm-kmp-rt
gfs2-kmp-rt-debuginfo
kernel-rt-debuginfo
dlm-kmp-rt-debuginfo
gfs2-kmp-rt
kernel-rt-devel-debuginfo
cluster-md-kmp-rt-debuginfo
kernel-rt-devel
kernel-syms-rt
kernel-rt-debugsource
cluster-md-kmp-rt
ocfs2-kmp-rt-debuginfo
gfs2-kmp-default
kernel-zfcpdump-debugsource
ocfs2-kmp-default-debuginfo
dlm-kmp-default-debuginfo
kernel-zfcpdump-debuginfo
cluster-md-kmp-default-debuginfo
ocfs2-kmp-default
dlm-kmp-default
gfs2-kmp-default-debuginfo
cluster-md-kmp-default
kernel-default-livepatch-devel
kernel-azure-devel
kernel-default-extra-debuginfo
kernel-docs
kernel-azure
kernel-azure-debugsource
kernel-azure-debuginfo
kernel-azure-devel-debuginfo
reiserfs-kmp-default-debuginfo
reiserfs-kmp-default
kernel-zfcpdump
kernel-64kb-devel-debuginfo
kernel-64kb-debuginfo
kernel-default-extra
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-raspi (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-2026-43491

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-livepatch-6_4_0-150700_7_62-rt - 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-debuginfo - 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
kernel-default-livepatch - 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-kvmsmall - update to 6.4.0-48.1
kernel-source - 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-macros - 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-default-debuginfo - 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-64kb-devel - 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-obs-build - 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-default-devel - 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-64kb - 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-default-base - addressed in versions 6.4.0-48.1.21.25, 6.4.0-150700.53.63.1.150700.17.37.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.62.1
kernel-source-rt - update to 6.4.0-150700.7.62.1
kernel-devel-rt - update to 6.4.0-150700.7.62.1
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
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-syms-rt - 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
gfs2-kmp-default - update to 6.4.0-150700.53.63.1
kernel-zfcpdump-debugsource - 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
kernel-zfcpdump-debuginfo - 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-azure-devel - update to 6.4.0-150700.53.63.1
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.63.1
kernel-docs - 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-debuginfo - update to 6.4.0-150700.53.63.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.63.1
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.63.1
reiserfs-kmp-default - update to 6.4.0-150700.53.63.1
kernel-zfcpdump - update to 6.4.0-150700.53.63.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.63.1
kernel-64kb-debuginfo - update to 6.4.0-150700.53.63.1
kernel-default-extra - update to 6.4.0-150700.53.63.1
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, 7.0.0-27.27
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, 7.0.0-1013.13
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-raspi (Ubuntu package) - addressed in versions 6.8.0-1061.65, 6.8.0-2050.52, 7.0.0-1014.14
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, 7.0.0-1009.9, 7.0.0-1010.10
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