HighCVE-2026-53199

    Linux Kernel: NULL Pointer Dereference (CVE-2026-53199)

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

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    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: hv_netvsc: use kmap_local_page in netvsc_copy_to_send_buf netvsc_copy_to_send_buf() copies page buffer entries into the VMBus send buffer using phys_to_virt() on the entry PFN. Entries for the RNDIS header and the skb linear data come from kmalloc'd memory and are always in the kernel direct map, but entries for skb fragments reference page cache or user pages, which on 32-bit x86 with CONFIG_HIGHMEM=y can live above the LOWMEM boundary.

    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 3.16..5.10.259
    • Linux Kernel lt 5.11..5.15.210
    • Linux Kernel lt 5.16..6.1.176
    • Linux Kernel lt 6.2..6.6.143
    • Linux Kernel lt 6.7..6.12.94
    • Linux Kernel lt 6.13..6.18.36
    • Linux Kernel lt 6.19..7.0.13
    Fixed in
    • Linux Kernel 5.10.259
    • Linux Kernel 5.15.210
    • Linux Kernel 6.1.176
    • Linux Kernel 6.6.143
    • Linux Kernel 6.12.94
    • Linux Kernel 6.18.36
    • Linux Kernel 7.0.13
    • Linux Kernel 7.1

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

    Metrics

    7.5

    Priority

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

    Source: Vendor (CNA), CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

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

    0.5 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 43.0

    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
    71.47 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
    7.5 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
    7.5
    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
    0.5 %
    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
    43.0
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    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 · automatable · Technical impact: partial
    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-476

    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: hv_netvsc: use kmap_local_page in netvsc_copy_to_send_buf netvsc_copy_to_send_buf() copies page buffer entries into the VMBus send buffer using phys_to_virt() on the entry PFN. Entries for the RNDIS header and the skb linear data come from kmalloc'd memory and are always in the kernel direct map, but entries for skb fragments reference page cache or user pages, which on 32-bit x86 with CONFIG_HIGHMEM=y can live above the LOWMEM boundary. For such a page phys_to_virt() returns an address outside the direct map and the subsequent memcpy() faults on the transmit softirq path, which is fatal. Map the pages with kmap_local_page() instead, handling two properties of the page buffer entries: - pb[i].pfn is a Hyper-V PFN at HV_HYP_PAGE_SIZE (4K) granularity, not a native PFN. Reconstruct the physical address first and derive the native page from it, so the mapping stays correct where PAGE_SIZE > HV_HYP_PAGE_SIZE (e.g. arm64 with 64K pages). - Since commit 41a6328b2c55 ("hv_netvsc: Preserve contiguous PFN grouping in the page buffer array"), an entry describes a full physically contiguous fragment and pb[i].len can exceed PAGE_SIZE, while kmap_local_page() maps a single page. Copy page by page, splitting at native page boundaries. The copy path only handles packets smaller than the send section size (6144 bytes by default); larger packets take the cp_partial path where only the RNDIS header is copied. So entries here are bounded by the section size and a copy is split at most once on 4K-page systems. On !CONFIG_HIGHMEM configs kmap_local_page() folds to page_address() and no mapping work is added.

    Source: suse_csaf, Ubuntu Security Notices, Debian LTS Advisories, BSI WID Portal, BSI CSAF, cvelistv5, Microsoft Security Update Guide, 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
    • 6.7 – < 6.12.94
    • 6.13 – < 6.18.36
    • 5.11 – < 5.15.210
    • 3.16 – < 5.10.259
    • —
    • 5.16 – < 6.1.176
    • 6.19 – < 7.0.13
    • 6.2 – < 6.6.143
    • 6.12.94
    • 6.18.36
    • 5.15.210
    • 5.10.259
    • 7.1
    • 6.1.176
    • 7.0.13
    • 6.6.143

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxubuntulinuxnoble
    Linuxdebianlinux-6.1bullseye
    Linuxubuntulinux-awsnoble
    Linuxubuntulinux-aws-6.8jammy
    Linuxubuntulinux-aws-fipsnoble
    Linuxubuntulinux-azurenoble
    Linuxubuntulinux-azure-6.8jammy
    Linuxubuntulinux-azure-fdenoble
    Linuxubuntulinux-azure-fde-6.8jammy
    Linuxubuntulinux-azure-fipsnoble
    Linuxubuntulinux-fipsnoble
    Linuxubuntulinux-gcpnoble
    Linuxubuntulinux-gcp-6.8jammy
    Linuxubuntulinux-gcp-fipsnoble
    Linuxubuntulinux-gkenoble
    Linuxubuntulinux-gkeopnoble
    Linuxubuntulinux-ibmnoble
    Linuxubuntulinux-ibm-6.8jammy
    Linuxubuntulinux-lowlatencynoble
    Linuxubuntulinux-lowlatency-hwe-6.8jammy
    Linuxubuntulinux-nvidiajammy
    Linuxubuntulinux-nvidianoble

    Weakness classes (CWE)

    • CWE-476NULL Pointer Dereference

      Base

      The product dereferences a pointer that it expects to be valid but is NULL.

      Entry at MITRE CWE-476

    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-476

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-476

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

    2. Record modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/004e9ecfe6c5384f9e0b2f6f6389d42ec22789af
      Referenceadded
      —
      https://git.kernel.org/stable/c/09b8a7aa5a341bb345dc492aac139525efa13515
      Referenceadded
      —
      https://git.kernel.org/stable/c/0b38870d81ab3a04c1ab0598d9d3285f5d9d0584
      Referenceadded
      —
      https://git.kernel.org/stable/c/16514afeb7d3d121072ba9a0b640d6c1c5507db0
      Referenceadded
      —
      https://git.kernel.org/stable/c/695c59cf7bf707e6ff8cea01916ee50e86616933
      Referenceadded
      —
      https://git.kernel.org/stable/c/918c0c988239aa5ab96b254e504d191af6191061
      Referenceadded
      —
      https://git.kernel.org/stable/c/a82d4251918f37d9c5aab7b365157669fb885ec3
      Referenceadded
      —
      https://git.kernel.org/stable/c/fe7221b4346418d27ec2daccfc09df6692b76f0b
      Referenceremoved
      https://git.kernel.org/stable/c/004e9ecfe6c5384f9e0b2f6f6389d42ec22789af
      —
      Referenceremoved
      https://git.kernel.org/stable/c/09b8a7aa5a341bb345dc492aac139525efa13515
      —
      Referenceremoved
      https://git.kernel.org/stable/c/0b38870d81ab3a04c1ab0598d9d3285f5d9d0584
      —
      Referenceremoved
      https://git.kernel.org/stable/c/16514afeb7d3d121072ba9a0b640d6c1c5507db0
      —
      Referenceremoved
      https://git.kernel.org/stable/c/695c59cf7bf707e6ff8cea01916ee50e86616933
      —
      Referenceremoved
      https://git.kernel.org/stable/c/918c0c988239aa5ab96b254e504d191af6191061
      —
      Referenceremoved
      https://git.kernel.org/stable/c/a82d4251918f37d9c5aab7b365157669fb885ec3
      —
      Referenceremoved
      https://git.kernel.org/stable/c/fe7221b4346418d27ec2daccfc09df6692b76f0b
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/004e9ecfe6c5384f9e0b2f6f6389d42ec22789af Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/09b8a7aa5a341bb345dc492aac139525efa13515 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/0b38870d81ab3a04c1ab0598d9d3285f5d9d0584 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/16514afeb7d3d121072ba9a0b640d6c1c5507db0 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/695c59cf7bf707e6ff8cea01916ee50e86616933 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/918c0c988239aa5ab96b254e504d191af6191061 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/a82d4251918f37d9c5aab7b365157669fb885ec3 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/fe7221b4346418d27ec2daccfc09df6692b76f0b Types: Patch
      —

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

    3. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: yes

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-53199","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:26:42.491117Z"}

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

    4. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (5.16 – before 6.1.176; 6.2 – before 6.6.143; 5.11 – before 5.15.210; 6.13 – before 6.18.36; 6.7 – before 6.12.94; 6.19 – before 7.0.13; 3.16 – before 5.10.259; 7 individual versions)
      Show 10 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:7.1:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.176 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.143 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.210 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.36 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.94 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.13 *cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc7:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 3.16 up to (excluding) 5.10.259
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/004e9ecfe6c5384f9e0b2f6f6389d42ec22789af Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/09b8a7aa5a341bb345dc492aac139525efa13515 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/0b38870d81ab3a04c1ab0598d9d3285f5d9d0584 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/16514afeb7d3d121072ba9a0b640d6c1c5507db0 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/695c59cf7bf707e6ff8cea01916ee50e86616933 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/918c0c988239aa5ab96b254e504d191af6191061 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/a82d4251918f37d9c5aab7b365157669fb885ec3 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/fe7221b4346418d27ec2daccfc09df6692b76f0b Types: Patch

      Source identifier: nvd@nist.gov

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