CVE-2026-35433: .NET Elevation of Privilege Vulnerability

Published May 12, 2026
·
Updated

.NET Elevation of Privilege Vulnerability

Other sources

Executive Summary:

Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 8.0, .NET 9.0, and .NET 10.0. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

Improper input validation in .NET allows an unauthorized attacker to elevate privileges locally.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/398

CVSS Details

- Version: 3.1 - Severity: High - Score: 7.3 - Vector: AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L/E:U/RL:O/RC:C - Weakness: CWE-122: Heap-based Buffer Overflow, CWE-20: Improper Input Validation

Affected Platforms

- Platforms: Windows - Architectures: All

<a name="affected-packages"></a>Affected Packages The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below

<a name=".NET 10"></a>.NET 10 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 10.0.0, <= 10.0.7 | 10.0.8 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 10.0.0, <= 10.0.7 | 10.0.8 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 10.0.0, <= 10.0.7 | 10.0.8

<a name=".NET 9"></a>.NET 9 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 9.0.0, <= 9.0.15 | 9.0.16 MMicrosoft.WindowsDesktop.App.Runtime.win-x64 | >= 9.0.0, <= 9.0.15 | 9.0.16 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 9.0.0, <= 9.0.15 | 9.0.16

<a name=".NET 8"></a>.NET 8 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 8.0.0, <= 8.0.26 | 8.0.27 MMicrosoft.WindowsDesktop.App.Runtime.win-x64 | >= 8.0.0, <= 8.0.26 | 8.0.27 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 8.0.0, <= 8.0.26 | 8.0.27

Advisory FAQ

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

If using a package listed in affected packages, an application is 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 8.0, NET 9.0, or .NET 10.0, as appropriate. If developers have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt them to update Visual Studio, which will also update the applications's .NET SDKs. 2. If a developer's application references the vulnerable package, update the package reference to the patched version. Developers can list the versions they have installed by running the dotnet --info command.

Once developers have installed the updated runtime or SDK, they can restart the app for the update to take effect.

Additionally, if developers have 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

A potential security issue has been found 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

Questions about this issue can be submitted to 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. Questions should be submitted thorugh 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-2026-35433

Acknowledgements

Ky0toFu

Revisions

V1.0 (May 12, 2026): Advisory published.

— GitHub

Heap-based buffer overflow in .NET allows an unauthorized attacker to elevate privileges locally.

— Microsoft

Affected Software

70 affected componentsFixes available
Microsoft .NET Framework=3.5, =4.8.1
Patch available
Microsoft .NET Framework=3.5, =4.8.1
Patch available
Microsoft .NET Framework=3.5, =4.8
Patch available
Microsoft .NET Framework=3.5
Patch available
Microsoft .NET Framework=3.5
Patch available
Microsoft .NET Framework=3.5, =4.8.1
Patch available
Microsoft .NET Framework=3.5, =4.8.1
Patch available
Microsoft .NET Framework=3.5, =4.7.2
Patch available
Microsoft .NET Framework=3.5, =4.8
Patch available
Microsoft .NET Framework=4.8
Patch available
Microsoft .NET Framework=4.8
Patch available
nuget/Microsoft.WindowsDesktop.App.Runtime.win-x86>=10.0.0<=10.0.7
10.0.8
nuget/Microsoft.WindowsDesktop.App.Runtime.win-x64>=10.0.0<=10.0.7
10.0.8
nuget/Microsoft.WindowsDesktop.App.Runtime.win-arm64>=10.0.0<=10.0.7
10.0.8
nuget/Microsoft.WindowsDesktop.App.Runtime.win-arm64>=9.0.0<=9.0.15
9.0.16
nuget/Microsoft.WindowsDesktop.App.Runtime.win-x64>=9.0.0<=9.0.15
9.0.16
nuget/Microsoft.WindowsDesktop.App.Runtime.win-x86>=9.0.0<=9.0.15
9.0.16
nuget/Microsoft.WindowsDesktop.App.Runtime.win-x86>=8.0.0<=8.0.26
8.0.27
nuget/Microsoft.WindowsDesktop.App.Runtime.win-x64>=8.0.0<=8.0.26
8.0.27
nuget/Microsoft.WindowsDesktop.App.Runtime.win-arm64>=8.0.0<=8.0.26
8.0.27
All of the following
Microsoft .NET Framework=4.8
Any of the following
Microsoft Windows 10 1607
Microsoft Windows Server 2012
Microsoft Windows Server 2012=r2
Microsoft Windows Server 2016
All of the following
Microsoft .NET Framework=3.5
Any of the following
Microsoft Windows Server 2012
Microsoft Windows Server 2012=r2
All of the following
Any of the following
Microsoft .NET>=8.0.0<8.0.27
Microsoft .NET>=9.0.0<9.0.16
Microsoft .NET>=10.0.0<10.0.8
Microsoft Windows
All of the following
Any of the following
Microsoft .NET Framework=3.5
Microsoft .NET Framework=4.8.1
Any of the following
Microsoft Windows 11 23h2
Microsoft Windows 11 23h2
Microsoft Windows 11 24h2
Microsoft Windows 11 24h2
Microsoft Windows 11 25h2
Microsoft Windows 11 25h2
Microsoft Windows 11 26h1
Microsoft Windows 11 26h1
Microsoft Windows Server 2022
Microsoft Windows Server 2025
All of the following
Any of the following
Microsoft .NET Framework=3.5
Microsoft .NET Framework=4.8
Any of the following
Microsoft Windows 10 1809
Microsoft Windows 10 1809
Microsoft Windows 10 21h2
Microsoft Windows 10 21h2
Microsoft Windows 10 22h2
Microsoft Windows 10 22h2
Microsoft Windows Server 2022
All of the following
Any of the following
Microsoft .NET Framework=3.5
Microsoft .NET Framework=4.7.2
Any of the following
Microsoft Windows 10 1809
Microsoft Windows 10 1809
Microsoft .NET Framework=3.5, =4.8.1
4.8.9334.0 and 4.8.4802.0
Microsoft .NET Framework=3.5, =4.8.1
4.8.9334.0 and 4.8.4802.0
Microsoft .NET Framework=3.5
4.8.9334.0 and 4.8.4802.0
Microsoft .NET Framework=3.5, =4.8.1
4.8.9334.0 and 4.8.4802.0
Microsoft .NET Framework=3.5
4.8.9334.0 and 4.8.4802.0
Microsoft .NET Framework=3.5, =4.8
4.8.9334.0 and 4.8.4802.0
Microsoft .NET Framework=3.5, =4.7.2
4.8.9334.0 and 4.8.4802.0
Microsoft .NET Framework=4.8
4.8.9334.0 and 4.8.4802.0
Microsoft .NET Framework=4.8
4.8.9334.0 and 4.8.4802.0
Microsoft .NET Framework=4.8
4.8.9334.0 and 4.8.4802.0
Microsoft .NET 9.0 installed on Windows<9.0.16
9.0.16
Microsoft .NET 10.0 installed on Windows<10.0.8
10.0.8
Microsoft .NET 8.0 installed on Windows<8.0.27
8.0.27

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

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

    Fixed in 10.0.8
  2. Upgrade

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

    Fixed in 10.0.8
  3. Upgrade

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

    Fixed in 10.0.8
  4. Upgrade

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

    Fixed in 9.0.16
  5. Upgrade

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

    Fixed in 9.0.16
  6. Upgrade

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

    Fixed in 9.0.16
  7. Upgrade

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

    Fixed in 8.0.27
  8. Upgrade

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

    Fixed in 8.0.27
  9. Upgrade

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

    Fixed in 8.0.27
  10. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087055
  11. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087049
  12. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087051
  13. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087054
  14. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087058
  15. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087048
  16. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087053
  17. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087059
  18. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087064
  19. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087061
  20. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087068
  21. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087066
  22. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087067
  23. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087063
  24. Upgrade

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

    Fixed in 4.8.9334.0 and 4.8.4802.0Patch KB5087065
  25. Upgrade

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

    Fixed in 9.0.16Patch KB5093448
  26. Upgrade

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

    Fixed in 10.0.8Patch KB5093446
  27. Upgrade

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

    Fixed in 8.0.27Patch KB5093447
  28. Upgrade

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

    Fixed in 8.0.27
  29. Upgrade

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

    Fixed in 9.0.16
  30. Upgrade

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

    Fixed in 8.0.27
  31. Upgrade

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

    Fixed in 9.0.16
  32. Upgrade

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

    Fixed in 10.0.8
  33. Upgrade

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

    Fixed in 10.0.8
  34. Upgrade

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

    Fixed in 8.0.27
  35. Upgrade

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

    Fixed in 9.0.16
  36. Upgrade

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

    Fixed in 10.0.8
  37. Configuration

    If you have deployed self-contained applications targeting any impacted versions, recompile and redeploy them after installing the updated .NET 8.0/9.0/10.0 runtime or SDK.

    Self-contained .NET applications targeting impacted versions Recompile-and-redeploy = required
  38. Operational

    After installing the updated runtime or SDK, restart the application for the update to take effect.

Event History

May 12, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
DescriptionWeakness
Updated
via Microsoft·02:00 PM
WeaknessAffected Software
CVE Published
via MITRE·04:58 PM
Data Sourced
via MITRE·04:58 PM
DescriptionSeverity
Data Sourced
via Red Hat·06:01 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·06:17 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·06:17 PM
Affected Software
May 18, 2026
Advisory Published
via GitHub·07:20 PM
Data Sourced
via GitHub·07:20 PM
DescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2026-35433?

The severity of CVE-2026-35433 is considered critical due to the potential for privilege escalation.

2

How do I fix CVE-2026-35433?

To fix CVE-2026-35433, install the latest security updates for the affected .NET versions from Microsoft.

3

Which .NET versions are affected by CVE-2026-35433?

CVE-2026-35433 affects .NET versions 3.5, 4.7.2, 4.8, and 8.0 through 10.0.

4

What impact does CVE-2026-35433 have on my system?

CVE-2026-35433 allows unauthorized users to elevate their privileges, which can compromise system integrity.

5

Is there a patch available for CVE-2026-35433?

Yes, patches are available for all affected .NET versions to mitigate CVE-2026-35433.

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