HighCVE-2026-70197

    .NET and Visual Studio Remote Code Execution Vulnerability (CVE-2026-70197)

    Published Last modified Sources: Red Hat, Msrc Update Guide, CVE.org, OSV, Hersteller, BSI

    What is affected, what to do

    Out-of-bounds write in .NET allows an unauthorized attacker to execute code over a network.

    Update Microsoft .NET 10.0 installed on Linux to version 10.0.403, Microsoft .NET 10.0 installed on Mac OS to version 10.0.403, Microsoft .NET 10.0 installed on Windows to version 10.0.403.

    Affected
    • Microsoft .NET 10.0 installed on Linux lt 10.0.0..10.0.403
    • Microsoft .NET 10.0 installed on Mac OS lt 10.0.0..10.0.403
    • Microsoft .NET 10.0 installed on Windows lt 10.0.0..10.0.403
    • Microsoft .NET 10.0 runtime lt 10.0.0..10.0.13
    • Microsoft .NET 11.0 installed on Linux lt 11.0.0-preview.1..11.0.100-rc.3
    • Microsoft .NET 11.0 installed on Mac OS lt 11.0.0-preview.1..11.0.100-rc.3
    • Microsoft .NET 11.0 installed on Windows lt 11.0.0-preview.1..11.0.100-rc.3.26522.148
    • Microsoft .NET 11.0 runtime lt 11.0.0..11.0.0-rc.2
    • Microsoft .NET 8.0 installed on Linux lt 8.0.0..8.0.427
    • Microsoft .NET 8.0 installed on Mac OS lt 8.0.0..8.0.427
    • Microsoft .NET 8.0 installed on Windows lt 8.0.0..8.0.427
    • Microsoft .NET 8.0 runtime lt 8.0.0..8.0.32
    • Microsoft .NET 9.0 installed on Linux lt 9.0.0..9.0.320
    • Microsoft .NET 9.0 installed on Mac OS lt 9.0.0..9.0.320
    • Microsoft .NET 9.0 installed on Windows lt 9.0.0..9.0.320
    • Microsoft .NET 9.0 runtime lt 9.0.0..9.0.21
    • Microsoft Visual Studio 2019 version 16.11 lt 16.11.0..16.11.61
    • Microsoft Visual Studio 2022 version 17.14 lt 17.14.0..17.14.43
    • Microsoft Visual Studio 2026 version 18.10 lt 18.10.0..18.10.4
    • Microsoft Visual Studio 2026 version 18.11 lt 18.11.0..18.11.2
    • Microsoft Visual Studio 2026 version 18.12 gte 18.12.0..*
    Fixed in
    • Microsoft .NET 10.0 installed on Linux 10.0.403
    • Microsoft .NET 10.0 installed on Mac OS 10.0.403
    • Microsoft .NET 10.0 installed on Windows 10.0.403
    • Microsoft .NET 10.0 runtime 10.0.13
    • Microsoft .NET 11.0 installed on Linux 11.0.100-rc.3
    • Microsoft .NET 11.0 installed on Mac OS 11.0.100-rc.3
    • Microsoft .NET 11.0 installed on Windows 11.0.100-rc.3.26522.148
    • Microsoft .NET 11.0 runtime 11.0.0-rc.2
    • Microsoft .NET 8.0 installed on Linux 8.0.427
    • Microsoft .NET 8.0 installed on Mac OS 8.0.427
    • Microsoft .NET 8.0 installed on Windows 8.0.427
    • Microsoft .NET 8.0 runtime 8.0.32
    • Microsoft .NET 9.0 installed on Linux 9.0.320
    • Microsoft .NET 9.0 installed on Mac OS 9.0.320
    • Microsoft .NET 9.0 installed on Windows 9.0.320
    • Microsoft .NET 9.0 runtime 9.0.21
    • Microsoft Visual Studio 2019 version 16.11 16.11.61
    • Microsoft Visual Studio 2022 version 17.14 17.14.43
    • Microsoft Visual Studio 2026 version 18.10 18.10.4
    • Microsoft Visual Studio 2026 version 18.11 18.11.2

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

    Metrics

    8.1

    Priority

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

    Source: NVD, CVSS v3

    8.1

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: Red Hat, Msrc Update Guide, CVE.org, OSV, Hersteller, BSI

    0.8 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 55.9

    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
    95.53 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
    8.1 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
    8.1
    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
    0.8 %
    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
    55.9
    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
    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-787

    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

    Out-of-bounds write in .NET allows an unauthorized attacker to execute code over a network.

    Source: redhat_csaf, Microsoft Security Update Guide, cvelistv5, NVD (NIST), OSV (Open Source Vulnerabilities), GitHub Security Advisories, CVE.org (MITRE), BSI WID Portal, BSI CSAF

    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
    Microsoft.NET 10.0 installed on Linux
    • 10.0.0 – < 10.0.403
    • 10.0.403
    Microsoft.NET 10.0 installed on Mac OS
    • 10.0.0 – < 10.0.403
    • 10.0.403
    Microsoft.NET 10.0 installed on Windows
    • 10.0.0 – < 10.0.403
    • 10.0.403
    Microsoft.NET 10.0 runtime
    • 10.0.0 – < 10.0.13
    • 10.0.13
    Microsoft.NET 11.0 installed on Linux
    • 11.0.0-preview.1 – < 11.0.100-rc.3
    • 11.0.100-rc.3
    Microsoft.NET 11.0 installed on Mac OS
    • 11.0.0-preview.1 – < 11.0.100-rc.3
    • 11.0.100-rc.3
    Microsoft.NET 11.0 installed on Windows
    • 11.0.0-preview.1 – < 11.0.100-rc.3.26522.148
    • 11.0.100-rc.3.26522.148
    Microsoft.NET 11.0 runtime
    • 11.0.0 – < 11.0.0-rc.2
    • 11.0.0-rc.2
    Microsoft.NET 8.0 installed on Linux
    • 8.0.0 – < 8.0.427
    • 8.0.427
    Microsoft.NET 8.0 installed on Mac OS
    • 8.0.0 – < 8.0.427
    • 8.0.427
    Microsoft.NET 8.0 installed on Windows
    • 8.0.0 – < 8.0.427
    • 8.0.427
    Microsoft.NET 8.0 runtime
    • 8.0.0 – < 8.0.32
    • 8.0.32
    Microsoft.NET 9.0 installed on Linux
    • 9.0.0 – < 9.0.320
    • 9.0.320
    Microsoft.NET 9.0 installed on Mac OS
    • 9.0.0 – < 9.0.320
    • 9.0.320
    Microsoft.NET 9.0 installed on Windows
    • 9.0.0 – < 9.0.320
    • 9.0.320
    Microsoft.NET 9.0 runtime
    • 9.0.0 – < 9.0.21
    • 9.0.21
    MicrosoftMicrosoft Visual Studio 2019 version 16.11
    • 16.11.0 – < 16.11.61
    • 16.11.61
    MicrosoftMicrosoft Visual Studio 2022 version 17.14
    • 17.14.0 – < 17.14.43
    • 17.14.43
    MicrosoftMicrosoft Visual Studio 2026 version 18.10
    • 18.10.0 – < 18.10.4
    • 18.10.4
    MicrosoftMicrosoft Visual Studio 2026 version 18.11
    • 18.11.0 – < 18.11.2
    • 18.11.2
    MicrosoftMicrosoft Visual Studio 2026 version 18.12
    • ≥ 18.12.0
    • —
    nugetmicrosoft.netcore.app.runtime.win-arm64
    • 10.0.6
    • 10.0.1
    • 8.0.29
    • 8.0.18
    • 8.0.31
    • 9.0.14
    • 8.0.28
    • 9.0.2
    • 8.0.21
    • 9.0.18
    • 8.0.2
    • 8.0.22
    • 10.0.7
    • 8.0.19
    • 8.0.6
    • 8.0.27
    • 8.0.5
    • 8.0.1
    • 8.0.13
    • 9.0.1
    • 9.0.9
    • 9.0.6
    • 8.0.3
    • 8.0.4
    • 9.0.20
    • 10.0.5
    • 9.0.15
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    Vendors and products

    Weakness classes (CWE)

    • CWE-787Out-of-bounds Write

      Base

      The product writes data past the end, or before the beginning, of the intended buffer.

      Entry at MITRE CWE-787

    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 modifiedMicrosoft

      1 individual change: Affected versions (publisher)

      Show the original change
      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/2026/70xxx/CVE-2026-70197.json">CVE-2026-70197</a>

      Source identifier: secure@microsoft.com

    2. Record modifiedMicrosoft

      1 individual change: Affected versions (publisher)

      Show the original change
      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/2026/70xxx/CVE-2026-70197.json">CVE-2026-70197</a>

      Source identifier: secure@microsoft.com

    3. Record modifiedCISA ADP

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

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentremoved
      {"id":"CVE-2026-70197","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-13T20:52:47.090964Z"}
      —
      SSVC assessmentadded
      —
      {"id":"CVE-2026-70197","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-08T00:00:00+00:00"}

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

    4. 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-2026-70197","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-13T20:52:47.090964Z"}

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

    5. ReceivedMicrosoft

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

      Weakness type: CWE-787

      Description added or changed

      Show 5 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      Out-of-bounds write in .NET allows an unauthorized attacker to execute code over a network.
      CVSSadded
      —
      AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
      Weakness type (CWE)added
      —
      CWE-787
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/70xxx/CVE-2026-70197.json">CVE-2026-70197</a>
      Referenceadded
      —
      https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70197

      Source identifier: secure@microsoft.com

    Linked advisories

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