MediumCVE-2019-0657

    Microsoft .NET Framework 4.5.2: Spoofing (CVE-2019-0657)

    Published Sources: OSV, CVE.org

    What is affected, what to do

    A vulnerability exists in certain .Net Framework API's and Visual Studio in the way they parse URL's, aka '.NET Framework and Visual Studio Spoofing Vulnerability'.

    The available sources name no fixed version. Check the vendor guidance in the references below.

    Affected
    • Microsoft .NET Framework 4.5.2 eq Windows 7 for 32-bit Systems Service Pack 1..Windows 7 for 32-bit Systems Service Pack 1
    • Microsoft .NET Framework 4.5.2 eq Windows 7 for x64-based Systems Service Pack 1..Windows 7 for x64-based Systems Service Pack 1
    • Microsoft .NET Framework 4.5.2 eq Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)..Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
    • Microsoft .NET Framework 4.5.2 eq Windows Server 2008 R2 for x64-based Systems Service Pack 1..Windows Server 2008 R2 for x64-based Systems Service Pack 1
    • Microsoft .NET Framework 4.5.2 eq Windows Server 2012..Windows Server 2012
    • Microsoft .NET Framework 4.5.2 eq Windows Server 2012 (Server Core installation)..Windows Server 2012 (Server Core installation)
    • Microsoft .NET Framework 4.5.2 eq Windows 8.1 for 32-bit systems..Windows 8.1 for 32-bit systems
    • Microsoft .NET Framework 4.5.2 eq Windows 8.1 for x64-based systems..Windows 8.1 for x64-based systems
    • Microsoft .NET Framework 4.5.2 eq Windows Server 2012 R2..Windows Server 2012 R2
    • Microsoft .NET Framework 4.5.2 eq Windows RT 8.1..Windows RT 8.1
    • Microsoft .NET Framework 4.5.2 eq Windows Server 2012 R2 (Server Core installation)..Windows Server 2012 R2 (Server Core installation)
    • Microsoft .NET Framework 4.5.2 eq Windows Server 2008 for 32-bit Systems Service Pack 2..Windows Server 2008 for 32-bit Systems Service Pack 2
    • Microsoft .NET Framework 4.5.2 eq Windows Server 2008 for x64-based Systems Service Pack 2..Windows Server 2008 for x64-based Systems Service Pack 2
    • Microsoft .NET Framework 4.6 eq Windows Server 2008 for 32-bit Systems Service Pack 2..Windows Server 2008 for 32-bit Systems Service Pack 2
    • Microsoft .NET Framework 4.6 eq Windows Server 2008 for x64-based Systems Service Pack 2..Windows Server 2008 for x64-based Systems Service Pack 2
    • Microsoft .NET Core eq 1..1
    • Microsoft .NET Core eq 2.1..2.1
    • Microsoft .NET Core eq 2.2..2.2
    • Microsoft Visual Studio eq 2017..2017
    • Microsoft .NET Framework 4.7.2 eq Windows 10 Version 1803 for 32-bit Systems..Windows 10 Version 1803 for 32-bit Systems
    • Microsoft .NET Framework 4.7.2 eq Windows 10 Version 1803 for x64-based Systems..Windows 10 Version 1803 for x64-based Systems
    • Microsoft .NET Framework 4.7.2 eq Windows Server, version 1803 (Server Core Installation)..Windows Server, version 1803 (Server Core Installation)
    • Microsoft .NET Framework 4.7.2 eq Windows 10 Version 1803 for ARM64-based Systems..Windows 10 Version 1803 for ARM64-based Systems
    • Microsoft .NET Framework 4.7.2 eq Windows 10 Version 1809 for 32-bit Systems..Windows 10 Version 1809 for 32-bit Systems
    • Microsoft .NET Framework 4.7.2 eq Windows 10 Version 1809 for x64-based Systems..Windows 10 Version 1809 for x64-based Systems
    • Microsoft .NET Framework 4.7.2 eq Windows Server 2019..Windows Server 2019
    • Microsoft .NET Framework 4.7.2 eq Windows Server 2019 (Server Core installation)..Windows Server 2019 (Server Core installation)
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2 eq Windows 10 for 32-bit Systems..Windows 10 for 32-bit Systems
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2 eq Windows 10 for x64-based Systems..Windows 10 for x64-based Systems
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows 7 for 32-bit Systems Service Pack 1..Windows 7 for 32-bit Systems Service Pack 1
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows 7 for x64-based Systems Service Pack 1..Windows 7 for x64-based Systems Service Pack 1
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)..Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows Server 2008 R2 for x64-based Systems Service Pack 1..Windows Server 2008 R2 for x64-based Systems Service Pack 1
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows Server 2012..Windows Server 2012
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows Server 2012 (Server Core installation)..Windows Server 2012 (Server Core installation)
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows 8.1 for 32-bit systems..Windows 8.1 for 32-bit systems
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows 8.1 for x64-based systems..Windows 8.1 for x64-based systems
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows Server 2012 R2..Windows Server 2012 R2
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows RT 8.1..Windows RT 8.1
    • Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 eq Windows Server 2012 R2 (Server Core installation)..Windows Server 2012 R2 (Server Core installation)
    • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 eq Windows Server 2016..Windows Server 2016
    • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 eq Windows 10 Version 1607 for 32-bit Systems..Windows 10 Version 1607 for 32-bit Systems
    • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 eq Windows 10 Version 1607 for x64-based Systems..Windows 10 Version 1607 for x64-based Systems
    • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 eq Windows Server 2016 (Server Core installation)..Windows Server 2016 (Server Core installation)
    • Microsoft .NET Framework 4.7/4.7.1/4.7.2 eq Windows 10 Version 1703 for 32-bit Systems..Windows 10 Version 1703 for 32-bit Systems
    • Microsoft .NET Framework 4.7/4.7.1/4.7.2 eq Windows 10 Version 1703 for x64-based Systems..Windows 10 Version 1703 for x64-based Systems
    • Microsoft .NET Framework 4.7.1/4.7.2 eq Windows 10 Version 1709 for 32-bit Systems..Windows 10 Version 1709 for 32-bit Systems
    • Microsoft .NET Framework 4.7.1/4.7.2 eq Windows 10 Version 1709 for x64-based Systems..Windows 10 Version 1709 for x64-based Systems
    • Microsoft .NET Framework 4.7.1/4.7.2 eq Windows Server, version 1709 (Server Core Installation)..Windows Server, version 1709 (Server Core Installation)
    • Microsoft .NET Framework 4.7.1/4.7.2 eq Windows 10 Version 1709 for ARM64-based Systems..Windows 10 Version 1709 for ARM64-based Systems
    • Microsoft PowerShell Core eq 6.1..6.1
    • Microsoft PowerShell Core eq 6.2..6.2
    • Microsoft Visual Studio 2017 eq version 15.9..version 15.9
    • Microsoft .NET Framework 3.5 eq Windows Server 2012..Windows Server 2012
    • Microsoft .NET Framework 3.5 eq Windows Server 2012 (Server Core installation)..Windows Server 2012 (Server Core installation)
    • Microsoft .NET Framework 3.5 eq Windows 8.1 for 32-bit systems..Windows 8.1 for 32-bit systems
    • Microsoft .NET Framework 3.5 eq Windows 8.1 for x64-based systems..Windows 8.1 for x64-based systems
    • Microsoft .NET Framework 3.5 eq Windows Server 2012 R2..Windows Server 2012 R2
    • Microsoft .NET Framework 3.5 eq Windows Server 2012 R2 (Server Core installation)..Windows Server 2012 R2 (Server Core installation)
    • Microsoft .NET Framework 3.5 eq Windows 10 for 32-bit Systems..Windows 10 for 32-bit Systems
    • Microsoft .NET Framework 3.5 eq Windows 10 for x64-based Systems..Windows 10 for x64-based Systems
    • Microsoft .NET Framework 3.5 eq Windows Server 2016..Windows Server 2016
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1607 for 32-bit Systems..Windows 10 Version 1607 for 32-bit Systems
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1607 for x64-based Systems..Windows 10 Version 1607 for x64-based Systems
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1703 for 32-bit Systems..Windows 10 Version 1703 for 32-bit Systems
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1703 for x64-based Systems..Windows 10 Version 1703 for x64-based Systems
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1709 for 32-bit Systems..Windows 10 Version 1709 for 32-bit Systems
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1709 for x64-based Systems..Windows 10 Version 1709 for x64-based Systems
    • Microsoft .NET Framework 3.5 eq Windows Server, version 1709 (Server Core Installation)..Windows Server, version 1709 (Server Core Installation)
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1803 for 32-bit Systems..Windows 10 Version 1803 for 32-bit Systems
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1803 for x64-based Systems..Windows 10 Version 1803 for x64-based Systems
    • Microsoft .NET Framework 3.5 eq Windows Server, version 1803 (Server Core Installation)..Windows Server, version 1803 (Server Core Installation)
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1803 for ARM64-based Systems..Windows 10 Version 1803 for ARM64-based Systems
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1809 for 32-bit Systems..Windows 10 Version 1809 for 32-bit Systems
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1809 for x64-based Systems..Windows 10 Version 1809 for x64-based Systems
    • Microsoft .NET Framework 3.5 eq Windows Server 2019..Windows Server 2019
    • Microsoft .NET Framework 3.5 eq Windows Server 2019 (Server Core installation)..Windows Server 2019 (Server Core installation)
    • Microsoft .NET Framework 3.5 eq Windows 10 Version 1709 for ARM64-based Systems..Windows 10 Version 1709 for ARM64-based Systems
    • Microsoft .NET Framework 3.0 eq Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2..Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2
    • Microsoft .NET Framework 3.0 eq Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2..Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2
    • Microsoft .NET Framework 3.0 eq Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2..Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2
    • Microsoft .NET Framework 2.0 eq Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2..Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2
    • Microsoft .NET Framework 3.5.1 eq Windows 7 for 32-bit Systems Service Pack 1..Windows 7 for 32-bit Systems Service Pack 1
    • Microsoft .NET Framework 3.5.1 eq Windows 7 for x64-based Systems Service Pack 1..Windows 7 for x64-based Systems Service Pack 1
    • Microsoft .NET Framework 3.5.1 eq Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)..Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
    • Microsoft .NET Framework 3.5.1 eq Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1..Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1
    • Microsoft .NET Framework 3.5.1 eq Windows Server 2008 R2 for x64-based Systems Service Pack 1..Windows Server 2008 R2 for x64-based Systems Service Pack 1

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    Metrics

    5.9

    Priority

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

    Source: NVD, CVSS v3

    5.9

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: OSV, CVE.org

    4.5 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 91.5

    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
    96.42 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
    5.9 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
    5.9
    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
    4.5 %
    Moderate — model estimates 1-10% 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
    91.5
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    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

    A vulnerability exists in certain .Net Framework API's and Visual Studio in the way they parse URL's, aka '.NET Framework and Visual Studio Spoofing Vulnerability'.

    Source: OSV (Open Source Vulnerabilities), cvelistv5, NVD (NIST)

    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 Core
    • 2.1
    • 1
    • 2.2
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    MicrosoftMicrosoft .NET Framework 2.0
    • Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2
    • —
    MicrosoftMicrosoft .NET Framework 3.0
    • Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2
    • Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2
    • Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2
    • —
    • —
    • —
    MicrosoftMicrosoft .NET Framework 3.5
    • Windows 8.1 for x64-based systems
    • Windows Server 2019
    • Windows 10 Version 1803 for x64-based Systems
    • Windows 10 Version 1709 for x64-based Systems
    • Windows 10 Version 1803 for ARM64-based Systems
    • Windows 10 Version 1809 for x64-based Systems
    • Windows Server 2019 (Server Core installation)
    • Windows Server 2016
    • Windows 10 Version 1703 for x64-based Systems
    • Windows 8.1 for 32-bit systems
    • Windows Server 2012 R2
    • Windows Server 2012
    • Windows 10 Version 1703 for 32-bit Systems
    • Windows 10 Version 1607 for 32-bit Systems
    • Windows Server 2012 R2 (Server Core installation)
    • Windows 10 for x64-based Systems
    • Windows 10 Version 1709 for ARM64-based Systems
    • Windows 10 Version 1607 for x64-based Systems
    • Windows 10 for 32-bit Systems
    • Windows 10 Version 1809 for 32-bit Systems
    • Windows Server 2012 (Server Core installation)
    • Windows 10 Version 1709 for 32-bit Systems
    • Windows Server, version 1803 (Server Core Installation)
    • Windows 10 Version 1803 for 32-bit Systems
    • Windows Server, version 1709 (Server Core Installation)
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    MicrosoftMicrosoft .NET Framework 3.5.1
    • Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
    • Windows 7 for 32-bit Systems Service Pack 1
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1
    • Windows 7 for x64-based Systems Service Pack 1
    • —
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    MicrosoftMicrosoft .NET Framework 4.5.2
    • Windows Server 2012 (Server Core installation)
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
    • Windows RT 8.1
    • Windows Server 2008 for x64-based Systems Service Pack 2
    • Windows 7 for 32-bit Systems Service Pack 1
    • Windows 8.1 for x64-based systems
    • Windows Server 2012 R2
    • Windows Server 2012
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1
    • Windows Server 2008 for 32-bit Systems Service Pack 2
    • Windows 8.1 for 32-bit systems
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    Vendors and products

    References & sources

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