Improper input validation in Linux kernel - CVE-2026-64531

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Main Vulnerability Database Vulnerabilities #VU139868

Improper input validation in Linux kernel - CVE-2026-64531

Published: July 28, 2026


Vulnerability identifier: #VU139868
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-2026-64531
CWE-ID: CWE-20
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 handling of oversized nested action attributes in openvswitch flow action construction when processing user-supplied openvswitch nested action attributes. A local user can supply specially crafted nested CLONE or CT actions to cause a denial of service.

The issue occurs because a generated nested action attribute can be closed with a truncated nla_len, causing later dump or teardown operations to walk a structurally different action stream than the one that was validated.


Affected software

Linux kernel
Debian Linux
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux Server - AUS
Ubuntu
openEuler
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
kpatch-patch-5_14_0-284_172_1 (Red Hat package)
kpatch-patch-5_14_0-687_10_1 (Red Hat package)
kpatch-patch-6_12_0-211_16_1 (Red Hat package)
kpatch-patch-5_14_0-427_126_1 (Red Hat package)
kpatch-patch-5_14_0-284_158_1 (Red Hat package)
kpatch-patch-5_14_0-427_113_1 (Red Hat package)
kpatch-patch-5_14_0-284_148_1 (Red Hat package)
kpatch-patch-5_14_0-427_100_1 (Red Hat package)
kpatch-patch-5_14_0-284_134_1 (Red Hat package)
kpatch-patch-5_14_0-427_84_1 (Red Hat package)
kpatch-patch-5_14_0-284_117_1 (Red Hat package)
kpatch-patch-5_14_0-427_68_2 (Red Hat package)
kernel (Red Hat package)
kernel-rt (Red Hat package)
linux-fips (Ubuntu package)
linux-lowlatency (Ubuntu package)
linux (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-azure (Ubuntu package)
linux-ibm (Ubuntu package)
linux-raspi (Ubuntu package)
linux-aws-5.15 (Ubuntu package)
linux-azure-fde-5.15 (Ubuntu package)
kernel
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-devel
kernel-extra-modules
kernel-source
kernel-tools
kernel-tools-debuginfo
kernel-headers
python3-perf-debuginfo
kernel-tools-devel
python3-perf
perf-debuginfo
perf
linux-gke (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-azure-6.8 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux (Debian package)
linux-nvidia-6.17 (Ubuntu package)
linux-oem-6.17 (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia-7.0 (Ubuntu package)
linux-nvidia-bos (Ubuntu package)
Red Hat OpenShift Container Platform

How to mitigate CVE-2026-64531

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kpatch-patch-5_14_0-284_172_1 (Red Hat package) - update to 1-7.el9_2
kpatch-patch-5_14_0-687_10_1 (Red Hat package) - update to 1-7.el9_8
kpatch-patch-6_12_0-211_16_1 (Red Hat package) - update to 1-7.el10_2
kpatch-patch-5_14_0-427_126_1 (Red Hat package) - update to 1-8.el9_4
kpatch-patch-5_14_0-284_158_1 (Red Hat package) - update to 1-10.el9_2
kpatch-patch-5_14_0-427_113_1 (Red Hat package) - update to 1-11.el9_4
kpatch-patch-5_14_0-284_148_1 (Red Hat package) - update to 1-12.el9_2
kpatch-patch-5_14_0-427_100_1 (Red Hat package) - update to 1-13.el9_4
kpatch-patch-5_14_0-284_134_1 (Red Hat package) - update to 1-14.el9_2
kpatch-patch-5_14_0-427_84_1 (Red Hat package) - update to 1-15.el9_4
kpatch-patch-5_14_0-284_117_1 (Red Hat package) - update to 1-20.el9_2
kpatch-patch-5_14_0-427_68_2 (Red Hat package) - update to 1-20.el9_4
Red Hat OpenShift Container Platform - update to 4.22.11
kernel (Red Hat package) - addressed in versions 5.14.0-284.186.1.el9_2, 5.14.0-427.143.1.el9_4, 5.14.0-687.38.1.el9_8, 6.12.0-211.46.1.el10_2
kernel-rt (Red Hat package) - update to 5.14.0-284.186.1.rt14.471.el9_2
linux-fips (Ubuntu package) - addressed in versions 5.15.0.190.111, 5.15.0-190.200+fips1, 5.15.0.1110.109, 5.15.0-1110.116
linux-lowlatency (Ubuntu package) - addressed in versions 5.15.0.190.157, 5.15.0-190.200
linux (Ubuntu package) - addressed in versions 5.15.0.190.169, 5.15.0-190.200, 5.15.0.1066.66, 5.15.0-1066.68, 5.15.0-1066.68~20.04.1, 5.15.0-1077.80, 5.15.0-1077.81, 5.15.0.1097.96, 5.15.0-1097.105, 5.15.0.1106.102, 5.15.0-1106.108, 5.15.0.1106.110, 5.15.0-1106.111, 5.15.0-1108.112~20.04.1, 5.15.0.1109.108, 5.15.0.1109.109, 5.15.0-1109.110, 5.15.0-1109.115, 5.15.0-1109.115~20.04.1, 5.15.0.1111.107, 5.15.0-1111.117, 5.15.0-1111.117~20.04.1, 5.15.0.1113.117, 5.15.0-1113.122, 5.15.0.1114.110, 5.15.0.1114.117, 5.15.0-1114.121, 5.15.0-1114.121+fips1, 5.15.0.1119.104, 5.15.0-1119.128+fips1, 6.8.0-138.138+fips1, 6.8.0-1035.36, 6.8.0-1048.52, 6.8.0-1060.63.1, 6.8.0-1063.66, 6.8.0-1063.66+fips1, 6.8.0-1065.73~22.04.1, 6.8.0-1066.74, 6.8.0-1066.74+fips1, 6.8.0-1066.74~22.04.1, 6.8.1-1058.59, 6.8.1-1058.59~22.04.1, 7.0.0-30.30, 7.0.0-30.30.1, 7.0.0-1011.11, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1017.17
linux-azure-5.15 (Ubuntu package) - addressed in versions 5.15.0-190.200~20.04.1, 5.15.0.1114.104, 5.15.0.1114.111, 5.15.0-1114.124, 5.15.0-1114.124+fips1, 5.15.0-1119.128~20.04.1
linux-azure (Ubuntu package) - addressed in versions 5.15.0-1055.55, 5.15.0.1055.57, 5.15.0.1119.117, 5.15.0-1119.128, 7.0.0-1011.11, 7.0.0-1012.12
linux-ibm (Ubuntu package) - addressed in versions 5.15.0.1108.105, 5.15.0-1108.112
linux-raspi (Ubuntu package) - addressed in versions 5.15.0.1108.106, 5.15.0-1108.111
linux-aws-5.15 (Ubuntu package) - addressed in versions 5.15.0-1114.121~20.04.1, 5.15.0-1114.124~20.04.1
linux-azure-fde-5.15 (Ubuntu package) - update to 5.15.0-1119.128~20.04.1
kernel - update to 6.6.0-145.3.29.160
bpftool - update to 6.6.0-145.3.29.160
bpftool-debuginfo - update to 6.6.0-145.3.29.160
kernel-debuginfo - update to 6.6.0-145.3.29.160
kernel-debugsource - update to 6.6.0-145.3.29.160
kernel-devel - update to 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
kernel-source - update to 6.6.0-145.3.29.160
kernel-tools - update to 6.6.0-145.3.29.160
kernel-tools-debuginfo - update to 6.6.0-145.3.29.160
kernel-headers - update to 6.6.0-145.3.29.160
python3-perf-debuginfo - update to 6.6.0-145.3.29.160
kernel-tools-devel - update to 6.6.0-145.3.29.160
python3-perf - update to 6.6.0-145.3.29.160
perf-debuginfo - update to 6.6.0-145.3.29.160
perf - update to 6.6.0-145.3.29.160
linux-gke (Ubuntu package) - addressed in versions 6.8.0-138.138.1, 6.8.0-138.138.1~22.04.1, 6.8.0-1061.69
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-138.138~22.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1032.34~22.04.1, 6.8.0-1063.66~22.04.1, 6.8.0-1064.71, 6.8.0-1064.71~22.04.1, 6.8.0-1065.73+fips1
linux-azure-6.8 (Ubuntu package) - addressed in versions 6.8.0-1060.63~22.04.1, 6.8.0-1063.64, 6.8.0-1063.64~22.04.1, 6.8.0-1063.67, 6.8.0-1065.73~22.04.1, 6.8.0-2052.54
linux-nvidia (Ubuntu package) - addressed in versions 6.8.0-1061.64, 6.8.0-1061.64.1, 6.8.0-1061.64~22.04.1, 7.0.0-1018.18
linux (Debian package) - update to 6.12.100-1
linux-nvidia-6.17 (Ubuntu package) - update to 6.17.0-1032.32
linux-oem-6.17 (Ubuntu package) - update to 6.17.0-1033.33
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-30.30~24.04.1
linux-gcp (Ubuntu package) - addressed in versions 7.0.0-1005.6, 7.0.0-1010.10
linux-oracle (Ubuntu package) - update to 7.0.0-1010.10
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia-7.0 (Ubuntu package) - update to 7.0.0-1018.18~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2018.18

External References

Related Security Bulletins