NULL pointer dereference in Linux kernel - CVE-2026-46086

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Main Vulnerability Database Vulnerabilities #VU132396

NULL pointer dereference in Linux kernel - CVE-2026-46086

Published: May 27, 2026


Vulnerability identifier: #VU132396
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-2026-46086
CWE-ID: CWE-476
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 null pointer dereference in br_fdb_fillbuf() when reading bridge forwarding database entries through the brforward_read() sysfs path during a concurrent local FDB update. A local user can trigger concurrent access to cause a denial of service.

The issue arises because RCU readers can observe inconsistent values of f->dst across a check and a later dereference.


Affected software

Linux kernel
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Workstation Extension 15
Anolis OS
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Basesystem Module
SUSE Linux Enterprise Live Patching
Public Cloud Module
Legacy Module
Development Tools Module
SUSE Real Time Module
Ubuntu
kernel-livepatch-6_4_0-150700_7_67-rt-debuginfo
kernel-livepatch-SLE15-SP7-RT_Update_18-debugsource
kernel-livepatch-6_4_0-150700_7_67-rt
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
kernel-rt (Red Hat package)
kernel-tools-libs
kernel-doc
kernel-abi-stablelists
python3-perf
perf
kernel-tools-libs-devel
kernel-tools
kernel-modules-extra
kernel-headers
bpftool
kernel
kernel-core
kernel-cross-headers
kernel-debug
kernel-debug-core
kernel-debug-devel
kernel-debug-modules
kernel-debug-modules-extra
kernel-devel
kernel-modules
kernel-rt-debuginfo
kernel-rt
kernel-source-rt
kernel-devel-rt
dlm-kmp-rt
cluster-md-kmp-rt
kernel-rt-debugsource
ocfs2-kmp-rt-debuginfo
kernel-syms-rt
cluster-md-kmp-rt-debuginfo
kernel-rt-devel
dlm-kmp-rt-debuginfo
gfs2-kmp-rt
ocfs2-kmp-rt
kernel-rt-devel-debuginfo
gfs2-kmp-rt-debuginfo
kernel-macros
kernel-source
kernel-docs
kernel-syms
cluster-md-kmp-default
dlm-kmp-default
gfs2-kmp-default
gfs2-kmp-default-debuginfo
cluster-md-kmp-default-debuginfo
dlm-kmp-default-debuginfo
kernel-zfcpdump-debugsource
ocfs2-kmp-default
ocfs2-kmp-default-debuginfo
kernel-obs-build
kernel-obs-build-debugsource
reiserfs-kmp-default
reiserfs-kmp-default-debuginfo
kernel-default-extra-debuginfo
kernel-default-extra
kernel-azure-debugsource
kernel-default-livepatch-devel
kernel-zfcpdump
kernel-default-livepatch
kernel-azure
kernel-azure-debuginfo
kernel-azure-devel-debuginfo
kernel-azure-devel
kernel-default-debugsource
kernel-default-debuginfo
kernel-default-devel
kernel-default-devel-debuginfo
kernel-64kb
kernel-64kb-debugsource
kernel-64kb-devel
kernel-64kb-devel-debuginfo
kernel-64kb-debuginfo
kernel-default
kernel-zfcpdump-debuginfo
kernel-default-base
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)
kernel (Red Hat package)
linux-raspi (Ubuntu package)

How to mitigate CVE-2026-46086

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-livepatch-6_4_0-150700_7_67-rt-debuginfo - 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 - 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
kernel-rt (Red Hat package) - update to 4.18.0-553.144.1.rt7.485.el8_10
kernel-tools-libs - update to 4.18.0-553.144.1.0.1
kernel-doc - update to 4.18.0-553.144.1.0.1
kernel-abi-stablelists - update to 4.18.0-553.144.1.0.1
python3-perf - update to 4.18.0-553.144.1.0.1
perf - update to 4.18.0-553.144.1.0.1
kernel-tools-libs-devel - update to 4.18.0-553.144.1.0.1
kernel-tools - update to 4.18.0-553.144.1.0.1
kernel-modules-extra - update to 4.18.0-553.144.1.0.1
kernel-headers - update to 4.18.0-553.144.1.0.1
bpftool - update to 4.18.0-553.144.1.0.1
kernel - update to 4.18.0-553.144.1.0.1
kernel-core - update to 4.18.0-553.144.1.0.1
kernel-cross-headers - update to 4.18.0-553.144.1.0.1
kernel-debug - update to 4.18.0-553.144.1.0.1
kernel-debug-core - update to 4.18.0-553.144.1.0.1
kernel-debug-devel - update to 4.18.0-553.144.1.0.1
kernel-debug-modules - update to 4.18.0-553.144.1.0.1
kernel-debug-modules-extra - update to 4.18.0-553.144.1.0.1
kernel-devel - update to 4.18.0-553.144.1.0.1
kernel-modules - update to 4.18.0-553.144.1.0.1
kernel-rt-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
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
kernel-rt-debugsource - update to 6.4.0-150700.7.67.1
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-syms-rt - update to 6.4.0-150700.7.67.1
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-rt-devel - update to 6.4.0-150700.7.67.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
gfs2-kmp-rt - update to 6.4.0-150700.7.67.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.67.1
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.67.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.67.1
kernel-devel - update to 6.4.0-150700.53.73.1
kernel-macros - 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-syms - update to 6.4.0-150700.53.73.1
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
gfs2-kmp-default - update to 6.4.0-150700.53.73.2
gfs2-kmp-default-debuginfo - 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-zfcpdump-debugsource - update to 6.4.0-150700.53.73.2
ocfs2-kmp-default - update to 6.4.0-150700.53.73.2
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.73.2
kernel-obs-build - update to 6.4.0-150700.53.73.2
kernel-obs-build-debugsource - update to 6.4.0-150700.53.73.2
reiserfs-kmp-default - update to 6.4.0-150700.53.73.2
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.73.2
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.73.2
kernel-default-extra - update to 6.4.0-150700.53.73.2
kernel-azure-debugsource - update to 6.4.0-150700.53.73.2
kernel-default-livepatch-devel - update to 6.4.0-150700.53.73.2
kernel-zfcpdump - update to 6.4.0-150700.53.73.2
kernel-default-livepatch - update to 6.4.0-150700.53.73.2
kernel-azure - update to 6.4.0-150700.53.73.2
kernel-azure-debuginfo - 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-debugsource - update to 6.4.0-150700.53.73.2
kernel-default-debuginfo - update to 6.4.0-150700.53.73.2
kernel-default-devel - update to 6.4.0-150700.53.73.2
kernel-default-devel-debuginfo - update to 6.4.0-150700.53.73.2
kernel-64kb - update to 6.4.0-150700.53.73.2
kernel-64kb-debugsource - update to 6.4.0-150700.53.73.2
kernel-64kb-devel - update to 6.4.0-150700.53.73.2
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.73.2
kernel-64kb-debuginfo - update to 6.4.0-150700.53.73.2
kernel-default - update to 6.4.0-150700.53.73.2
kernel-zfcpdump-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
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-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
kernel (Red Hat package) - update to 6.12.0-211.40.1.el10_2
linux-raspi (Ubuntu package) - update to 7.0.0-1014.14

External References

Related Security Bulletins