HighCVE-2026-43502

    Linux Kernel: security vulnerability (CVE-2026-43502)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: net/rds: handle zerocopy send cleanup before the message is queued A zerocopy send can fail after user pages have been pinned but before the message is attached to the sending socket. The purge path currently infers zerocopy state from rm->m_rs, so an unqueued message can be cleaned up as if it owned normal payload pages.

    An exploit is publicly available. Update Linux Kernel to version 5.10.258, Linux Kernel to version 5.15.209, Linux Kernel to version 6.1.175.

    Affected
    • Linux Kernel lt 4.17..5.10.258
    • Linux Kernel lt 5.11..5.15.209
    • Linux Kernel lt 5.16..6.1.175
    • Linux Kernel lt 6.2..6.6.140
    • Linux Kernel lt 6.7..6.12.88
    • Linux Kernel lt 6.13..6.18.30
    • Linux Kernel lt 6.19..7.0.7
    Fixed in
    • Linux Kernel 5.10.258
    • Linux Kernel 5.15.209
    • Linux Kernel 6.1.175
    • Linux Kernel 6.6.140
    • Linux Kernel 6.12.88
    • Linux Kernel 6.18.30
    • Linux Kernel 7.0.7
    • 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: Ubuntu, SUSE, Debian LTS, Siemens ProductCERT, BSI, CVE.org, Msrc Update Guide, EUVD

    0.3 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 25.5

    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
    61.81 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
    PoC (publicly reported)
    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
    0.3 %
    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
    25.5
    Elevated — this CVE ranks above at least 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: proof of concept · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 14 September 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-401

    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

    In the Linux kernel, the following vulnerability has been resolved: net/rds: handle zerocopy send cleanup before the message is queued A zerocopy send can fail after user pages have been pinned but before the message is attached to the sending socket. The purge path currently infers zerocopy state from rm->m_rs, so an unqueued message can be cleaned up as if it owned normal payload pages. However, zerocopy ownership is really determined by the presence of op_mmp_znotifier, regardless of whether the message has reached the socket queue. Capture op_mmp_znotifier up front in rds_message_purge() and use it as the cleanup discriminator. If the message is already associated with a socket, keep the existing completion path. Otherwise, drop the pinned page accounting directly and release the notifier before putting the payload pages. This keeps early send failure cleanup consistent with the zerocopy lifetime rules without changing the normal queued completion path.

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

    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
    • 6.7 – < 6.12.88
    • 4.17 – < 5.10.258
    • 6.2 – < 6.6.140
    • 6.19 – < 7.0.7
    • 5.11 – < 5.15.209
    • —
    • 6.13 – < 6.18.30
    • 6.1.175
    • 6.12.88
    • 5.10.258
    • 6.6.140
    • 7.0.7
    • 5.15.209
    • 7.1
    • 6.18.30
    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-oracle-7.0noble
    Linuxlinuxlinux_kernel7.1
    Linuxlinuxlinux_kernel—

    Weakness classes (CWE)

    • CWE-401Missing Release of Memory after Effective Lifetime

      Variant

      The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

      Entry at MITRE CWE-401

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    Reference tagged as exploitgithub.com (opens in a new tab)PoC (publicly reported)reported, not verified—

    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 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/2026/43xxx/CVE-2026-43502.json">CVE-2026-43502</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

    2. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: proof of concept, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentchanged
      {"id":"CVE-2026-43502","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-14T14:09:05.627504Z"}
      {"id":"CVE-2026-43502","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-14T00:00:00+00:00"}

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

    3. Record modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/0f5c185fc79a59ee9991234dd6d2a3e5afa6e75b
      Referenceadded
      —
      https://git.kernel.org/stable/c/14ef6fd18db2494098b21e0471bf27a1d8e9993e
      Referenceadded
      —
      https://git.kernel.org/stable/c/1e262db7675e27f42c3f3f47d6011855f4454f24
      Referenceadded
      —
      https://git.kernel.org/stable/c/21d70744e6d3bbf9293aa1ee6fba7c53ad75275e
      Referenceadded
      —
      https://git.kernel.org/stable/c/3abc8983b2bae3f487f77d9da5527d7d6b210d46
      Referenceadded
      —
      https://git.kernel.org/stable/c/44b550d88b267320459d518c0743a241ab2108fa
      Referenceadded
      —
      https://git.kernel.org/stable/c/46662f7dc59475995609bf3e9d27eb36f4acf26f
      Referenceadded
      —
      https://git.kernel.org/stable/c/e9aefdc5c53fe9aed108c14e3d155710a1bb14c9
      Referenceremoved
      https://git.kernel.org/stable/c/0f5c185fc79a59ee9991234dd6d2a3e5afa6e75b
      —
      Referenceremoved
      https://git.kernel.org/stable/c/14ef6fd18db2494098b21e0471bf27a1d8e9993e
      —
      Referenceremoved
      https://git.kernel.org/stable/c/1e262db7675e27f42c3f3f47d6011855f4454f24
      —
      Referenceremoved
      https://git.kernel.org/stable/c/21d70744e6d3bbf9293aa1ee6fba7c53ad75275e
      —
      Referenceremoved
      https://git.kernel.org/stable/c/3abc8983b2bae3f487f77d9da5527d7d6b210d46
      —
      Referenceremoved
      https://git.kernel.org/stable/c/44b550d88b267320459d518c0743a241ab2108fa
      —
      Referenceremoved
      https://git.kernel.org/stable/c/46662f7dc59475995609bf3e9d27eb36f4acf26f
      —
      Referenceremoved
      https://git.kernel.org/stable/c/e9aefdc5c53fe9aed108c14e3d155710a1bb14c9
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/0f5c185fc79a59ee9991234dd6d2a3e5afa6e75b Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/14ef6fd18db2494098b21e0471bf27a1d8e9993e Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/1e262db7675e27f42c3f3f47d6011855f4454f24 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/21d70744e6d3bbf9293aa1ee6fba7c53ad75275e Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/3abc8983b2bae3f487f77d9da5527d7d6b210d46 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/44b550d88b267320459d518c0743a241ab2108fa Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/46662f7dc59475995609bf3e9d27eb36f4acf26f Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/e9aefdc5c53fe9aed108c14e3d155710a1bb14c9 Types: Patch
      —

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

    4. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: proof of concept, automatable: no

      Weakness type: CWE-401

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-401
      Referenceadded
      —
      https://github.com/NebuSec/CyberMeowfia/tree/main/security-research/Linux-CVE-2026-43502-openSUSE-6.4.0-150600
      SSVC assessmentadded
      —
      {"id":"CVE-2026-43502","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-14T14:09:05.627504Z"}

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

    One NVD translation into another language is hidden.

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