HighCVE-2026-46015

    Linux Kernel: security vulnerability (CVE-2026-46015)

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

    What is affected, what to do

    A flaw was found in the Linux kernel's TCP networking subsystem. When an established network connection is migrated between listener sockets within the same SO_REUSEPORT group, applications waiting for new connections may not be properly notified.

    Update Linux Kernel to version 5.15.209, Linux Kernel to version 6.1.175, Linux Kernel to version 6.6.140.

    Affected
    • Linux Kernel lt 5.14..5.15.209
    • Linux Kernel lt 5.16..6.1.175
    • 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 5.15.209
    • Linux Kernel 6.1.175
    • 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

    7.8

    Priority

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

    Source: Vendor (CNA), CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

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

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 3.0

    Show all metrics
    Severity
    High
    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
    57.09 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
    7.8 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
    7.8
    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
    3.0
    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
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 16 October 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-408

    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
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    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

    A flaw was found in the Linux kernel's TCP networking subsystem. When an established network connection is migrated between listener sockets within the same SO_REUSEPORT group, applications waiting for new connections may not be properly notified. This can cause poll(), epoll_wait(), and blocking accept() calls to remain unresponsive indefinitely, leading to a Denial of Service (DoS) for affected applications.

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

    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
    • 5.16 – < 6.1.175
    • 6.19 – < 7.0.4
    • 5.14 – < 5.15.209
    • 6.2 – < 6.6.140
    • 6.13 – < 6.18.27
    • —
    • 6.7 – < 6.12.86
    • 6.1.175
    • 7.0.4
    • 5.15.209
    • 6.6.140
    • 6.18.27
    • 7.1
    • 6.12.86
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinux-6.1bullseye
    Linuxlinuxlinux_kernel—

    Weakness classes (CWE)

    • CWE-408Incorrect Behavior Order: Early Amplification

      Base

      The product allows an entity to perform a legitimate but expensive operation before authentication or authorization has taken place.

      Entry at MITRE CWE-408

    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 modifiedCISA ADP

      Weakness type: CWE-408

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-408

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-46015","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:18:52.666086Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    3. Record modifiedSiemens ADP

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/46xxx/CVE-2026-46015.json">CVE-2026-46015</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-457936.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

    4. Record modifiedLinux

      Show 21 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/12625b4da84caf4d84a04988710a7b9bcf702b18
      Referenceadded
      —
      https://git.kernel.org/stable/c/14e9bb6eba8f59dcc637702e4744ae5e30660d76
      Referenceadded
      —
      https://git.kernel.org/stable/c/3864c6ba1e041bc75342353a70fa2a2c6f909923
      Referenceadded
      —
      https://git.kernel.org/stable/c/7aa7933a5607b1e5b56f322d17265c1d0ea02c51
      Referenceadded
      —
      https://git.kernel.org/stable/c/83bb57635d7cbafde32f865b577ecfd969f02337
      Referenceadded
      —
      https://git.kernel.org/stable/c/ab5fdcd535645f6dbe6e9e21d96a08d141e88b4b
      Referenceadded
      —
      https://git.kernel.org/stable/c/bebd058ef40c67a81fe6d9ee8beaa4ede90e0704
      Referenceremoved
      https://git.kernel.org/stable/c/12625b4da84caf4d84a04988710a7b9bcf702b18
      —
      Referenceremoved
      https://git.kernel.org/stable/c/14e9bb6eba8f59dcc637702e4744ae5e30660d76
      —
      Referenceremoved
      https://git.kernel.org/stable/c/3864c6ba1e041bc75342353a70fa2a2c6f909923
      —
      Referenceremoved
      https://git.kernel.org/stable/c/7aa7933a5607b1e5b56f322d17265c1d0ea02c51
      —
      Referenceremoved
      https://git.kernel.org/stable/c/83bb57635d7cbafde32f865b577ecfd969f02337
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ab5fdcd535645f6dbe6e9e21d96a08d141e88b4b
      —
      Referenceremoved
      https://git.kernel.org/stable/c/bebd058ef40c67a81fe6d9ee8beaa4ede90e0704
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/12625b4da84caf4d84a04988710a7b9bcf702b18 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/14e9bb6eba8f59dcc637702e4744ae5e30660d76 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/3864c6ba1e041bc75342353a70fa2a2c6f909923 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/7aa7933a5607b1e5b56f322d17265c1d0ea02c51 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/83bb57635d7cbafde32f865b577ecfd969f02337 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/ab5fdcd535645f6dbe6e9e21d96a08d141e88b4b Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/bebd058ef40c67a81fe6d9ee8beaa4ede90e0704 Types: Patch
      —

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

    5. 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-2026-46015.json">CVE-2026-46015</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-019113.html

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

    Show one older change

    1. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (6.7 – before 6.12.86; 5.16 – before 6.1.175; 6.2 – before 6.6.140; 5.14 – before 5.15.209; 6.13 – before 6.18.27; 6.19 – before 7.0.4)
      Show 9 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      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) 5.16 up to (excluding) 6.1.175 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.140 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.14 up to (excluding) 5.15.209 *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
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/12625b4da84caf4d84a04988710a7b9bcf702b18 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/14e9bb6eba8f59dcc637702e4744ae5e30660d76 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/3864c6ba1e041bc75342353a70fa2a2c6f909923 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/7aa7933a5607b1e5b56f322d17265c1d0ea02c51 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/83bb57635d7cbafde32f865b577ecfd969f02337 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/ab5fdcd535645f6dbe6e9e21d96a08d141e88b4b Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/bebd058ef40c67a81fe6d9ee8beaa4ede90e0704 Types: Patch

      Source identifier: nvd@nist.gov

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