IRONSMITHINTEL
HIGHCVSS7.8
|
Actively Exploited
|CISA KEV|CVE-2020-1147|Auth: none — unauthenticated|Reboot: required|Manual only

KB4484436: Windows Server Security Update (July 2020)

Microsoft .NET Framework, Microsoft SharePoint, and Visual Studio contain a remote code execution vulnerability when the software fails to check the source markup of XML file input. Successful exploitation allows an attacker to execute code in the context of the process responsible for deserialization of the XML content.

Published Jul 14, 2020 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A local attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2022-05-03 under CISA BOD 22-01.

How the attack worksNo clicks needed

This vulnerability affects Microsoft .NET Framework, SharePoint, Visual Studio. A remote code execution vulnerability exists in .NET Framework, Microsoft SharePoint, and Visual Studio when the software fails to check the source markup of XML file input, aka '.NET Framework, SharePoint Server, and Visual Studio Remote Code Execution Vulnerability'. Exploitation requires local access, low attack complexity, no authentication required, and user interaction required.

Am I affected?Quick check

Probably yes if any of these apply:

●SharePoint Administrators
●IT Security
●Running .net core: 2.1, 3.1; .net framework: 2.0, 3.0, 3.5, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.6, 4.6.1, 4.8, 3.5.1, 4.5.2; sharepoint enterprise server: 2013, 2016; sharepoint server: 2010, 2019; visual studio 2017: 15.0 ≤ v ≤ 15.9; visual studio 2019: 16.0 ≤ v ≤ 16.6
Fixed inKB4484436, KB4484443, KB4484453, KB4484460, KB4566466, KB4566467, KB4566468, KB4566469, KB4578962, KB4578963, KB4578966, KB4578968, KB4578969, KB4578971, KB4578972, KB4578973, KB4578974, KB4578975, KB4578976, KB4578977, KB4579976, KB4579977, KB4579978, KB4579979, KB4579980, KB4580327, KB4580328, KB4580330, KB4580346 (applies to 103 product versions)
Real-world incidentsWhat we've seen

Active exploitation documented in the wild. Threat-research write-up: http://packetstormsecurity.com/files/158694/SharePoint-DataSet-DataTable-Deserialization.html

How to patch

Manual download

For air-gapped servers or out-of-band deployment. Microsoft Update Catalog returns every OS-version variant of this update.

↗ Microsoft Update CatalogKB4484436

Manual remediation steps

Apply the Microsoft Security Update

Microsoft has released an official security update that fixes this vulnerability.

Required KB Updates

    1
    KB4484436 — https://support.microsoft.com/help/4484436
    1
    KB4484443 — https://support.microsoft.com/help/4484443
    1
    KB4484453 — https://support.microsoft.com/help/4484453
    1
    KB4484460 — https://support.microsoft.com/help/4484460
    1
    KB4566466 — https://support.microsoft.com/help/4566466
    1
    KB4566467 — https://support.microsoft.com/help/4566467
    1
    KB4566468 — https://support.microsoft.com/help/4566468
    1
    KB4566469 — https://support.microsoft.com/help/4566469
    1
    KB4578962 — https://support.microsoft.com/help/4578962
    1
    KB4578963 — https://support.microsoft.com/help/4578963
    1
    KB4578966 — https://support.microsoft.com/help/4578966
    1
    KB4578968 — https://support.microsoft.com/help/4578968
    1
    KB4578969 — https://support.microsoft.com/help/4578969
    1
    KB4578971 — https://support.microsoft.com/help/4578971
    1
    KB4578972 — https://support.microsoft.com/help/4578972
    1
    KB4578973 — https://support.microsoft.com/help/4578973
    1
    KB4578974 — https://support.microsoft.com/help/4578974
    1
    KB4578975 — https://support.microsoft.com/help/4578975
    1
    KB4578976 — https://support.microsoft.com/help/4578976
    1
    KB4578977 — https://support.microsoft.com/help/4578977
    1
    KB4579976 — https://support.microsoft.com/help/4579976
    1
    KB4579977 — https://support.microsoft.com/help/4579977
    1
    KB4579978 — https://support.microsoft.com/help/4579978
    1
    KB4579979 — https://support.microsoft.com/help/4579979
    1
    KB4579980 — https://support.microsoft.com/help/4579980
    1
    KB4580327 — https://support.microsoft.com/help/4580327
    1
    KB4580328 — https://support.microsoft.com/help/4580328
    1
    KB4580330 — https://support.microsoft.com/help/4580330
    1
    KB4580346 — https://support.microsoft.com/help/4580346

Supersedes: KB4484400, KB4484402, KB4484405, KB4484414, KB4576478, 4576945, KB4576478, 4576945 , KB4576627, 4577324, KB4576628, KB4576629, KB4576630, KB4576631, KB4576947, 4576484, KB4577015, KB4577032, KB4577041, KB4577049

Affected Products

    1
    .NET Core 2.1
    1
    .NET Core 3.1
    1
    Microsoft .NET Framework 2.0 Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2
    1
    Microsoft .NET Framework 2.0 Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2
    1
    Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2
    1
    Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2
    1
    Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for 32-bit Systems
    1
    Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for x64-based Systems
    1
    Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016
    1
    Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016 (Server Core installation)
    1
    Microsoft .NET Framework 3.5 AND 4.6/4.6.1/4.6.2 on Windows 10 for 32-bit Systems
    1
    Microsoft .NET Framework 3.5 AND 4.6/4.6.1/4.6.2 on Windows 10 for x64-based Systems
    1
    Microsoft .NET Framework 3.5 AND 4.7.1/4.7.2 on Windows 10 Version 1709 for 32-bit Systems
    1
    Microsoft .NET Framework 3.5 AND 4.7.1/4.7.2 on Windows 10 Version 1709 for ARM64-based Systems
    1
    Microsoft .NET Framework 3.5 AND 4.7.1/4.7.2 on Windows 10 Version 1709 for x64-based Systems
    1
    Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1803 for 32-bit Systems
    1
    Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1803 for ARM64-based Systems
    1
    Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1803 for x64-based Systems
    1
    Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for 32-bit Systems
    1
    Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for ARM64-based Systems
    1
    (…83 more product versions)

Installation Methods

Windows Update (recommended)

1
Settings → Windows Update → Check for updates
2
The security update is offered if your system is in scope
3
Restart when prompted (may or may not be required for this update)

Microsoft Update Catalog (manual download)

1
Open https://catalog.update.microsoft.com
2
Search for KB4484436
3
Download the package matching your OS architecture and Windows build
4
Run the .msu installer with administrator privileges
5
Restart when prompted

WSUS / SCCM / Intune

Approve KB4484436 for the affected products in your update management console.

Microsoft Download Center Links

    1
    http://aka.ms/vs/15/release/latest
    1
    http://aka.ms/vs/16/release/latest
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4565577
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4565578
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB4565579
    1
    (…42 more)

Verification

Confirm the update is installed:

Get-HotFix | Where-Object { $_.HotFixID -in @('KB4484436','KB4484443','KB4484453','KB4484460','KB4566466','KB4566467','KB4566468','KB4566469','KB4578962','KB4578963','KB4578966','KB4578968','KB4578969','KB4578971','KB4578972','KB4578973','KB4578974','KB4578975','KB4578976','KB4578977','KB4579976','KB4579977','KB4579978','KB4579979','KB4579980','KB4580327','KB4580328','KB4580330','KB4580346') }

References

    1
    Microsoft Security Response Center: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1147
    1
    KB article: https://support.microsoft.com/help/4566466
    1
    KB article: https://support.microsoft.com/help/4566467
    1
    KB article: https://support.microsoft.com/help/4566468
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2020-1147
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-1147

Discovery Credit

Oleksandr Mirosh (@olekmirosh) from Micro Focus Fortify, Jonathan Birch of Microsoft Office Security Team, Markus Wulftange (@mwulftange)

PowerShell automationComing soon

No tested PowerShell script for this entry yet. We’re prioritising automation based on user demand.

References

↗ CVE-2020-1147↗ MSRC Advisory↗ NVD↗ KBKB4484436