Linux Distros Unpatched Vulnerability : CVE-2026-43403

high Nessus Plugin ID 313431

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- nsfs: tighten permission checks for ns iteration ioctls Even privileged services should not necessarily be able to see other privileged service's namespaces so they can't leak information to each other. Use may_see_all_namespaces() helper that centralizes this policy until the nstree adapts. (CVE-2026-43403)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

See Also

https://access.redhat.com/security/cve/cve-2026-43403

https://ubuntu.com/security/CVE-2026-43403

Plugin Details

Severity: High

ID: 313431

File Name: unpatched_CVE_2026_43403.nasl

Version: 1.6

Type: Local

Agent: unix

Family: Misc.

Published: 5/8/2026

Updated: 5/29/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.3

CVSS v2

Risk Factor: Low

Base Score: 2.1

Temporal Score: 1.8

Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:N/A:N

CVSS Score Source: CVE-2026-43403

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 8.1

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:U/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-rt-core, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-6.17, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules-core, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-core, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-5.19, p-cpe:/a:redhat:enterprise_linux:kernel-doc, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.3, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-devel, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.11, p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-hwe, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.8, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.17, p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules-extra, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.2, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug, p-cpe:/a:redhat:enterprise_linux:kernel, p-cpe:/a:redhat:enterprise_linux:kernel-64k-devel, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules-extra, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.0, p-cpe:/a:canonical:ubuntu_linux:linux-raspi, p-cpe:/a:redhat:enterprise_linux:kernel-modules, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules-extra, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-oracle, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.19, p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules-core, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-realtime, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.13, p-cpe:/a:redhat:enterprise_linux:kernel-64k-core, p-cpe:/a:canonical:ubuntu_linux:linux-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-6.14, p-cpe:/a:redhat:enterprise_linux:kernel-tools-libs-devel, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.2, p-cpe:/a:redhat:enterprise_linux:kernel-core, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.11, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-6.14, p-cpe:/a:redhat:enterprise_linux:kernel-tools-libs, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.0, p-cpe:/a:redhat:enterprise_linux:kernel-abi-stablelists, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-kvm, p-cpe:/a:redhat:enterprise_linux:kernel-tools, p-cpe:/a:canonical:ubuntu_linux:linux-aws, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.13, p-cpe:/a:redhat:enterprise_linux:perf, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-devel-matched, p-cpe:/a:canonical:ubuntu_linux:linux-oem, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.5, p-cpe:/a:redhat:enterprise_linux:kernel-devel-matched, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.11, p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules-core, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.11, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-core, p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel, p-cpe:/a:canonical:ubuntu_linux:linux-gke-4.15, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.8, p-cpe:/a:redhat:enterprise_linux:kernel-rt, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.0, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.8, p-cpe:/a:redhat:enterprise_linux:kernel-devel, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-core, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.14, p-cpe:/a:redhat:enterprise_linux:kernel-rt-devel, p-cpe:/a:canonical:ubuntu_linux:linux-starfive-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.14, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-devel, p-cpe:/a:redhat:enterprise_linux:kernel-uki-virt-addons, p-cpe:/a:canonical:ubuntu_linux:linux-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-azure, p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules-extra, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-modules-core, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.14, p-cpe:/a:redhat:enterprise_linux:kernel-64k-devel-matched, p-cpe:/a:redhat:enterprise_linux:kernel-rt-modules, p-cpe:/a:redhat:enterprise_linux:kernel-debug-core, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules-core, p-cpe:/a:canonical:ubuntu_linux:linux-gke-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-starfive-6.5, cpe:/o:canonical:ubuntu_linux:25.10, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.6, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.8, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-gkeop-5.4, p-cpe:/a:redhat:enterprise_linux:kernel-64k, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-6.11, p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules-core, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-6.14, p-cpe:/a:redhat:enterprise_linux:rv, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-modules-core, p-cpe:/a:redhat:enterprise_linux:kernel-uki-virt, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-core, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-6.2, p-cpe:/a:redhat:enterprise_linux:libperf, p-cpe:/a:canonical:ubuntu_linux:linux-allwinner-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.11, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-gkeop-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.13, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules-core, p-cpe:/a:redhat:enterprise_linux:kernel-debug-modules, p-cpe:/a:canonical:ubuntu_linux:linux-raspi-realtime, p-cpe:/a:redhat:enterprise_linux:python3-perf, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-intel-iot-realtime, p-cpe:/a:canonical:ubuntu_linux:linux-gkeop, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-edge, p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel-matched, p-cpe:/a:redhat:enterprise_linux:rtla, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.13, p-cpe:/a:canonical:ubuntu_linux:linux, p-cpe:/a:redhat:enterprise_linux:kernel-64k-modules, p-cpe:/a:redhat:enterprise_linux:kernel-modules-extra-matched, p-cpe:/a:redhat:enterprise_linux:kernel-debug-uki-virt, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.11, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.2, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump, p-cpe:/a:canonical:ubuntu_linux:linux-gke, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-intel-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-gke-5.4, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-debug-core, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k-modules-extra, p-cpe:/a:canonical:ubuntu_linux:linux-azure-edge, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.11, p-cpe:/a:redhat:enterprise_linux:kernel-rt-64k, p-cpe:/a:redhat:enterprise_linux:kernel-modules-extra, p-cpe:/a:redhat:enterprise_linux:kernel-64k-debug-modules, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.5, p-cpe:/a:redhat:enterprise_linux:kernel-zfcpdump-modules, p-cpe:/a:redhat:enterprise_linux:kernel-modules-core, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-azure-nvidia-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.17, p-cpe:/a:redhat:enterprise_linux:kernel-debug, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-starfive-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.1, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-riscv, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.10

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 5/8/2026

Reference Information

CVE: CVE-2026-43403