CVE-2026-83520: .NET Remote Code Execution Vulnerability

Published Oct 13, 2026
·
Updated

.NET Remote Code Execution Vulnerability

Other sources

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.WindowsDesktop.App.Runtime (WPF). This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

Restrictive XAML and XPS security fixes block unsafe URI fetching and navigation, propagate untrusted-input state through hyperlink navigation, add TrueType font protection and XAML nesting-depth limits, and avoid caching positive DNS zone-policy decisions.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/467

CVSS Details

- Version: 3.1 - Severity: High - Score: 8.8 - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

- Weakness: CWE-502 (Deserialization of Untrusted Data) Affected Platforms

- Platforms: Windows - Architectures: All

<a name="affected-packages"></a>Affected Packages

The vulnerability affects Microsoft .NET projects that use an affected package version listed below.

Package name | Affected version | Patched version ------------ | ---------------- | --------------- Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 10.0.0, <= 10.0.12 | 10.0.13 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 10.0.0, <= 10.0.12 | 10.0.13 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 10.0.0, <= 10.0.12 | 10.0.13 Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 8.0.0, <= 8.0.31 | 8.0.32 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 8.0.0, <= 8.0.31 | 8.0.32 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 8.0.0, <= 8.0.31 | 8.0.32 Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 9.0.0, <= 9.0.20 | 9.0.21 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 9.0.0, <= 9.0.20 | 9.0.21 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 9.0.0, <= 9.0.20 | 9.0.21

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

If using a package listed in affected packages, you're exposed to the vulnerability.

<a name="how-fix"></a>How do I fix the issue?

1. To fix the issue please install the latest version of .NET. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs. 2. If your application references the vulnerable package, update the package reference to the patched version. You can list the versions you have installed by running the dotnet --info command.

Once you have installed the updated runtime or SDK, restart your apps for the update to take effect.

Additionally, if you've deployed self-contained applications targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-83520

Acknowledgements

- Dr.-Ing Ashar Javed (@soaj1664ashar) - Vincent55 Yang

Revisions

V1.0 (10/13/2026): Advisory published.

— GitHub

Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code over a network.

— Microsoft

Affected Software

50 affected componentsFixes available
Microsoft .NET Framework=4.8.1
4.8.9363.0
nuget/microsoft.windowsdesktop.app.runtime.win-x86>=9.0.0<=9.0.20
9.0.21
nuget/microsoft.windowsdesktop.app.runtime.win-x64>=9.0.0<=9.0.20
9.0.21
nuget/microsoft.windowsdesktop.app.runtime.win-arm64>=9.0.0<=9.0.20
9.0.21
nuget/microsoft.windowsdesktop.app.runtime.win-x86>=8.0.0<=8.0.31
8.0.32
nuget/microsoft.windowsdesktop.app.runtime.win-x64>=8.0.0<=8.0.31
8.0.32
nuget/microsoft.windowsdesktop.app.runtime.win-arm64>=8.0.0<=8.0.31
8.0.32
nuget/microsoft.windowsdesktop.app.runtime.win-x86>=10.0.0<=10.0.12
10.0.13
nuget/microsoft.windowsdesktop.app.runtime.win-x64>=10.0.0<=10.0.12
10.0.13
nuget/microsoft.windowsdesktop.app.runtime.win-arm64>=10.0.0<=10.0.12
10.0.13
nuget/microsoft.windowsdesktop.app.runtime.win-x86>=11.0.0-preview.1<=11.0.0-rc.1
11.0.0-rc.2
nuget/microsoft.windowsdesktop.app.runtime.win-x64>=11.0.0-preview.1<=11.0.0-rc.1
11.0.0-rc.2
nuget/microsoft.windowsdesktop.app.runtime.win-arm64>=11.0.0-preview.1<=11.0.0-rc.1
11.0.0-rc.2
All of the following
Microsoft .NET runtime>=11.0<11.0.0-rc.2
11.0.0-rc.2
Microsoft Windows*
Microsoft Visual Studio 2022>=17.14<17.14.42
17.14.42
Microsoft .NET Framework=3.5, =4.8.1, >=2.0.50727<2.0.50727.9188, >=3.0.30729<3.0.30729.9171
2.0.50727.91883.0.30729.91714.8.9363.0
Microsoft .NET Framework=4.6.2, >=4.7<4.7.4150.0, =4.7.1, =4.7.2
4.7.4150.0
Microsoft .NET Framework>=4.8<4.8.4811.0
4.8.4811.0
Microsoft .NET Framework>=4.8<4.8.4811.0
4.8.4811.0
Microsoft .NET Framework>=4.8<4.8.4811.0
4.8.4811.0
Microsoft .NET Framework=3.5, >=4.8<4.8.4811.0, >=2.0.50727<2.0.50727.9188, >=3.0.30729<3.0.30729.9171
2.0.50727.91883.0.30729.91714.8.4811.0
Microsoft Visual Studio 2026>=18.10<18.10.4
18.10.4
Microsoft .NET Framework=3.5, >=4.8<4.8.4811.0, >=2.0.50727<2.0.50727.9073, >=3.0.30729<3.0.30729.9070
2.0.50727.90733.0.30729.90704.8.4811.0
Microsoft .NET Framework=4.6.2, >=4.7<4.7.4150.0, =4.7.1, =4.7.2
4.7.4150.0
All of the following
Microsoft .NET runtime>=9.0<9.0.21
9.0.21
Microsoft Windows*
Microsoft .NET Framework=3.5, >=4.8<4.8.4811.0, >=2.0.50727<2.0.50727.9188, >=3.0.30729<3.0.30729.9171
2.0.50727.91883.0.30729.91714.8.4811.0
Microsoft .NET Framework=3.5, =4.6.2, >=4.7<4.7.4150.0, =4.7.1, =4.7.2, >=2.0.50727<2.0.50727.9073, >=3.0.30729<3.0.30729.9070
2.0.50727.90733.0.30729.90704.7.4150.0
Microsoft .NET Framework=3.5, =4.7.2, >=2.0.50727<2.0.50727.9073, >=3.0.30729<3.0.30729.9070
2.0.50727.90733.0.30729.90704.7.4150.0
Microsoft .NET Framework=3.5, =4.6.2, >=4.7<4.7.4150.0, =4.7.1, =4.7.2, >=2.0.50727<2.0.50727.8987, >=3.0.30729<3.0.30729.8982
2.0.50727.89873.0.30729.89824.7.4150.0
Microsoft .NET Framework=3.5, >=2.0.50727<2.0.50727.8987, >=3.0.30729<3.0.30729.8982
2.0.50727.89873.0.30729.8982
Microsoft .NET Framework=3.5, >=2.0.50727<2.0.50727.9188, >=3.0.30729<3.0.30729.9171
2.0.50727.91883.0.30729.9171
All of the following
Microsoft .NET runtime>=8.0<8.0.32
8.0.32
Microsoft Windows*
Microsoft .NET Framework=3.5, >=2.0.50727<2.0.50727.8987, >=3.0.30729<3.0.30729.8982
2.0.50727.89873.0.30729.8982
Microsoft .NET Framework=3.5, =4.8.1, >=2.0.50727<2.0.50727.9188, >=3.0.30729<3.0.30729.9171
2.0.50727.91883.0.30729.91714.8.10008.0
Microsoft .NET Framework=3.5, =4.8.1, >=2.0.50727<2.0.50727.9188, >=3.0.30729<3.0.30729.9171
2.0.50727.91883.0.30729.91714.8.9363.0
All of the following
Microsoft .NET runtime>=10.0<10.0.13
10.0.13
Microsoft Windows*
Microsoft .NET Framework=3.5, =4.8.1, >=2.0.50727<2.0.50727.9188, >=3.0.30729<3.0.30729.9171
2.0.50727.91883.0.30729.91714.8.9363.0
ubuntu/dotnet7*
alpine/dotnet10-runtime<10.0.13-r0
10.0.13-r0
alpine/dotnet10-runtime<10.0.13-r0
10.0.13-r0
alpine/dotnet8-runtime<8.0.32-r0
8.0.32-r0
alpine/dotnet8-runtime<8.0.32-r0
8.0.32-r0
alpine/dotnet8-runtime<8.0.32-r0
8.0.32-r0
alpine/dotnet9-runtime<9.0.21-r0
9.0.21-r0
alpine/dotnet9-runtime<9.0.21-r0
9.0.21-r0
alpine/dotnet9-runtime<9.0.21-r0
9.0.21-r0

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 4.8.9363.0Patch KB5127691
  2. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-x86 to a version that resolves this vulnerability.

    Fixed in 9.0.21
  3. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-x64 to a version that resolves this vulnerability.

    Fixed in 9.0.21
  4. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-arm64 to a version that resolves this vulnerability.

    Fixed in 9.0.21
  5. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-x86 to a version that resolves this vulnerability.

    Fixed in 8.0.32
  6. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-x64 to a version that resolves this vulnerability.

    Fixed in 8.0.32
  7. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-arm64 to a version that resolves this vulnerability.

    Fixed in 8.0.32
  8. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-x86 to a version that resolves this vulnerability.

    Fixed in 10.0.13
  9. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-x64 to a version that resolves this vulnerability.

    Fixed in 10.0.13
  10. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-arm64 to a version that resolves this vulnerability.

    Fixed in 10.0.13
  11. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-x86 to a version that resolves this vulnerability.

    Fixed in 11.0.0-rc.2
  12. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-x64 to a version that resolves this vulnerability.

    Fixed in 11.0.0-rc.2
  13. Upgrade

    Upgrade nuget/Microsoft.WindowsDesktop.App.Runtime.win-arm64 to a version that resolves this vulnerability.

    Fixed in 11.0.0-rc.2
  14. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 11.0.0-rc.2
  15. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 17.14.42
  16. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.9188Fixed in 3.0.30729.9171Fixed in 4.8.9363.0Patch KB5127690
  17. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 4.7.4150.0Patch KB5127668
  18. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 4.8.4811.0Patch KB5127688
  19. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 4.8.4811.0Patch KB5127686
  20. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 4.8.4811.0Patch KB5127684
  21. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.9188Fixed in 3.0.30729.9171Fixed in 4.8.9363.0Patch KB5127692
  22. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.9188Fixed in 3.0.30729.9171Fixed in 4.8.4811.0Patch KB5127683
  23. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 18.10.4
  24. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.9073Fixed in 3.0.30729.9070Fixed in 4.8.4811.0Patch KB5127685
  25. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 4.7.4150.0Patch KB5127667
  26. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.9188Fixed in 3.0.30729.9171Fixed in 4.8.4811.0Patch KB5127687
  27. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 9.0.21Patch KB5130035
  28. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.9073Fixed in 3.0.30729.9070Fixed in 4.7.4150.0Patch KB5127666
  29. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.8987Fixed in 3.0.30729.8982Fixed in 4.7.4150.0Patch KB5126868
  30. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.9188Fixed in 3.0.30729.9171Patch KB5127696
  31. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.8987Fixed in 3.0.30729.8982Patch KB5127664
  32. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.8987Fixed in 3.0.30729.8982Patch KB5127660
  33. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.9188Fixed in 3.0.30729.9171Fixed in 4.8.10008.0Patch KB5127694
  34. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 8.0.32Patch KB5130034
  35. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.13Patch KB5130036
  36. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.9188Fixed in 3.0.30729.9171Fixed in 4.8.9363.0Patch KB5127693
  37. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.0.50727.9188Fixed in 3.0.30729.9171Fixed in 4.8.9363.0Patch KB5127689
  38. Upgrade

    Upgrade Microsoft.WindowsDesktop.App.Runtime.win-arm64, Microsoft.WindowsDesktop.App.Runtime.win-x64, Microsoft.WindowsDesktop.App.Runtime.win-x86 to a version that resolves this vulnerability.

    Fixed in 8.0.32
  39. Upgrade

    Upgrade Microsoft.WindowsDesktop.App.Runtime.win-arm64, Microsoft.WindowsDesktop.App.Runtime.win-x64, Microsoft.WindowsDesktop.App.Runtime.win-x86 to a version that resolves this vulnerability.

    Fixed in 9.0.21
  40. Upgrade

    Upgrade Microsoft.WindowsDesktop.App.Runtime.win-arm64, Microsoft.WindowsDesktop.App.Runtime.win-x64, Microsoft.WindowsDesktop.App.Runtime.win-x86 to a version that resolves this vulnerability.

    Fixed in 10.0.13
  41. Upgrade

    Upgrade Microsoft.WindowsDesktop.App.Runtime.win-arm64, Microsoft.WindowsDesktop.App.Runtime.win-x64, Microsoft.WindowsDesktop.App.Runtime.win-x86 to a version that resolves this vulnerability.

    Fixed in 11.0.0-rc.2
  42. Operational

    Recompile and redeploy self-contained applications targeting any impacted .NET versions.

  43. Operational

    Restart applications after installing the updated .NET runtime or SDK.

Event History

Oct 13, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeaknessAffected Software
CVE Published
via MITRE·07:01 PM
Data Sourced
via MITRE·07:01 PM
DescriptionSeverity
Data Sourced
via OSV·07:19 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·07:19 PM
DescriptionSeverityWeakness
Advisory Published
via GitHub·08:48 PM
Data Sourced
via GitHub·08:48 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What must an attacker do to exploit this vulnerability?

The attacker can attempt exploitation over a network without prior privileges, but user interaction is required. Exploitation involves untrusted data being deserialized by an affected .NET component.

2

What could a successful exploit allow?

A successful exploit could allow code execution with high impact to confidentiality, integrity, and availability.

3

Which Microsoft products are listed as affected?

The affected software list includes Microsoft .NET Framework; .NET 8.0, 9.0, 10.0, and 11.0 installed on Windows; Visual Studio 2022; and Visual Studio 2026.

Company

Resources

Contact

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