MediumCVE-2026-46026

    Linux Kernel: security vulnerability (CVE-2026-46026)

    Published Last modified Sources: SUSE, Debian LTS, Ubuntu, Siemens ProductCERT, BSI, CVE.org, EUVD, Msrc Update Guide

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: net: qrtr: ns: Limit the maximum number of lookups Current code does no bound checking on the number of lookups a client can perform. Though the code restricts the lookups to local clients, there is still a possibility of a malicious local client sending a flood of NEW_LOOKUP messages over the same socket.

    Update Linux Kernel to version 5.10.259, Linux Kernel to version 5.15.210, Linux Kernel to version 6.1.176.

    Affected
    • Linux Kernel lt 5.7..5.10.259
    • Linux Kernel lt 5.11..5.15.210
    • Linux Kernel lt 5.16..6.1.176
    • Linux Kernel lt 6.2..6.6.140
    • Linux Kernel lt 6.7..6.12.86
    • Linux Kernel lt 6.13..6.18.27
    • Linux Kernel lt 6.19..7.0.4
    Fixed in
    • Linux Kernel 5.10.259
    • Linux Kernel 5.15.210
    • Linux Kernel 6.1.176
    • Linux Kernel 6.6.140
    • Linux Kernel 6.12.86
    • Linux Kernel 6.18.27
    • Linux Kernel 7.0.4
    • Linux Kernel 7.1

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    5.5

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    5.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: SUSE, Debian LTS, Ubuntu, Siemens ProductCERT, BSI, CVE.org, EUVD, Msrc Update Guide

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 2.9

    Show all metrics
    Severity
    Medium
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    45.44 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    5.5 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    5.5
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.1 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    2.9
    Low — this CVE sits in the lower 10% of all CVEs scored today.
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    In the Linux kernel, the following vulnerability has been resolved: net: qrtr: ns: Limit the maximum number of lookups Current code does no bound checking on the number of lookups a client can perform. Though the code restricts the lookups to local clients, there is still a possibility of a malicious local client sending a flood of NEW_LOOKUP messages over the same socket. Fix this issue by limiting the maximum number of lookups to 64 globally. Since the nameserver allows only atmost one local observer, this global lookup count will ensure that the lookups stay within the limit. Note that, limit of 64 is chosen based on the current platform requirements. If requirement changes in the future, this limit can be increased.

    Source: suse_csaf, Debian LTS Advisories, Ubuntu Security Notices, siemens_advisory, BSI WID Portal, BSI CSAF, NVD (NIST), ENISA EUVD, CVE.org (MITRE), Microsoft Security Update Guide, cvelistv5

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    LinuxLinux
    • 6.19 – < 7.0.4
    • 6.2 – < 6.6.140
    • 5.11 – < 5.15.210
    • 5.7 – < 5.10.259
    • 6.13 – < 6.18.27
    • —
    • 5.16 – < 6.1.176
    • 6.7 – < 6.12.86
    • 7.0.4
    • 6.6.140
    • 5.15.210
    • 5.10.259
    • 6.18.27
    • 7.1
    • 6.1.176
    • 6.12.86
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxdebianlinux-6.1bullseye
    Linuxubuntulinux-gcp-5.15focal
    Linuxlinuxlinux_kernel—

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedLinux

      Show 21 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/0dbec101a7076e9b1e4bd1876f7cf07c56ff4ce3
      Referenceadded
      —
      https://git.kernel.org/stable/c/20855cef7e659ef84ac73251256fa530819b2346
      Referenceadded
      —
      https://git.kernel.org/stable/c/2b930bc77e00cb27e1d6e1d497b3b596283465ef
      Referenceadded
      —
      https://git.kernel.org/stable/c/5640227d9a21c6a8be249a10677b832e7f40dc55
      Referenceadded
      —
      https://git.kernel.org/stable/c/6e3675251fcea06caecc61eb76462467558adfa6
      Referenceadded
      —
      https://git.kernel.org/stable/c/76adf8f69b0bb3ab20be7c58f5d555027332d113
      Referenceadded
      —
      https://git.kernel.org/stable/c/91cb30b6bb1880ba0748ca059bef50b8ac13793d
      Referenceadded
      —
      https://git.kernel.org/stable/c/bd69e0e8a7643ba5385f19f479e8e3da71f8d495
      Referenceremoved
      https://git.kernel.org/stable/c/0dbec101a7076e9b1e4bd1876f7cf07c56ff4ce3
      —
      Referenceremoved
      https://git.kernel.org/stable/c/20855cef7e659ef84ac73251256fa530819b2346
      —
      Referenceremoved
      https://git.kernel.org/stable/c/2b930bc77e00cb27e1d6e1d497b3b596283465ef
      —
      Referenceremoved
      https://git.kernel.org/stable/c/5640227d9a21c6a8be249a10677b832e7f40dc55
      —
      Referenceremoved
      https://git.kernel.org/stable/c/6e3675251fcea06caecc61eb76462467558adfa6
      —
      Referenceremoved
      https://git.kernel.org/stable/c/76adf8f69b0bb3ab20be7c58f5d555027332d113
      —
      Referenceremoved
      https://git.kernel.org/stable/c/91cb30b6bb1880ba0748ca059bef50b8ac13793d
      —
      Referenceremoved
      https://git.kernel.org/stable/c/bd69e0e8a7643ba5385f19f479e8e3da71f8d495
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/0dbec101a7076e9b1e4bd1876f7cf07c56ff4ce3 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/20855cef7e659ef84ac73251256fa530819b2346 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/2b930bc77e00cb27e1d6e1d497b3b596283465ef Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/5640227d9a21c6a8be249a10677b832e7f40dc55 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/76adf8f69b0bb3ab20be7c58f5d555027332d113 Types: Patch
      —

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    2. Record modifiedSiemens ADP

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/46xxx/CVE-2026-46026.json">CVE-2026-46026</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

      Source identifier: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

    3. Record modifiedLinux

      Show 4 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/6e3675251fcea06caecc61eb76462467558adfa6
      Referenceadded
      —
      https://git.kernel.org/stable/c/91cb30b6bb1880ba0748ca059bef50b8ac13793d
      Referenceadded
      —
      https://git.kernel.org/stable/c/bd69e0e8a7643ba5385f19f479e8e3da71f8d495
      Affected versions (publisher)changed
      Linux, Linux
      Linux, Linux

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    4. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (6.7 – before 6.12.86; 6.13 – before 6.18.27; 6.19 – before 7.0.4; 5.7 – before 6.6.140)

      CVSS V3.1: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

      Show 8 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      CVSSadded
      —
      AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
      Weakness type (CWE)added
      —
      NVD-CWE-noinfo
      Product configurationadded
      —
      OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.86 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.27 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.4 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.7 up to (excluding) 6.6.140
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/0dbec101a7076e9b1e4bd1876f7cf07c56ff4ce3 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/20855cef7e659ef84ac73251256fa530819b2346 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/2b930bc77e00cb27e1d6e1d497b3b596283465ef Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/5640227d9a21c6a8be249a10677b832e7f40dc55 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/76adf8f69b0bb3ab20be7c58f5d555027332d113 Types: Patch

      Source identifier: nvd@nist.gov

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