GHSA-8X9C-MQXV-Q2PP

Vulnerability from github – Published: 2026-05-18 19:20 – Updated: 2026-05-18 19:20
VLAI
Summary
Microsoft Security Advisory CVE-2026-35433 – .NET Elevation of Privilege Vulnerability
Details

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

Affected Packages

The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below

.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

.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

.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

How do I know if I am affected?

If using a package listed in affected packages, an application is exposed to the vulnerability.

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.

Show details on source website

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 8.0.26"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.WindowsDesktop.App.Runtime.win-arm64"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.0.27"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 8.0.26"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.WindowsDesktop.App.Runtime.win-x64"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.0.27"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 8.0.26"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.WindowsDesktop.App.Runtime.win-x86"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.0.27"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 9.0.15"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.WindowsDesktop.App.Runtime.win-x86"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.0.0"
            },
            {
              "fixed": "9.0.16"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 9.0.15"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.WindowsDesktop.App.Runtime.win-x64"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.0.0"
            },
            {
              "fixed": "9.0.16"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 9.0.15"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.WindowsDesktop.App.Runtime.win-arm64"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.0.0"
            },
            {
              "fixed": "9.0.16"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 10.0.7"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.WindowsDesktop.App.Runtime.win-arm64"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "10.0.0"
            },
            {
              "fixed": "10.0.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 10.0.7"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.WindowsDesktop.App.Runtime.win-x64"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "10.0.0"
            },
            {
              "fixed": "10.0.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 10.0.7"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.WindowsDesktop.App.Runtime.win-x86"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "10.0.0"
            },
            {
              "fixed": "10.0.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-35433"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-122",
      "CWE-20"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-18T19:20:19Z",
    "nvd_published_at": "2026-05-12T18:17:13Z",
    "severity": "HIGH"
  },
  "details": "## Executive Summary: \n\nMicrosoft 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.\n\nImproper input validation in .NET allows an unauthorized attacker to elevate privileges locally. \n\n## Announcement\n\nAnnouncement for this issue can be found at https://github.com/dotnet/announcements/issues/398\n\n## CVSS Details\n\n- **Version:** 3.1\n- **Severity:** High\n- **Score:** 7.3\n- **Vector:** AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L/E:U/RL:O/RC:C \n- **Weakness:** CWE-122: Heap-based Buffer Overflow, CWE-20: Improper Input Validation\n\n## Affected Platforms\n\n- **Platforms:** Windows\n- **Architectures:** All\n\n## \u003ca name=\"affected-packages\"\u003e\u003c/a\u003eAffected Packages\nThe vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below\n\n### \u003ca name=\".NET 10\"\u003e\u003c/a\u003e.NET 10\nPackage name | Affected version | Patched version\n------------ | ---------------- | -------------------------\n[Microsoft.WindowsDesktop.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-arm64)               | \u003e= 10.0.0, \u003c= 10.0.7 | 10.0.8\n[Microsoft.WindowsDesktop.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x64)                   | \u003e= 10.0.0, \u003c= 10.0.7 | 10.0.8\n[Microsoft.WindowsDesktop.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x86)                   | \u003e= 10.0.0, \u003c= 10.0.7 | 10.0.8\n\n### \u003ca name=\".NET 9\"\u003e\u003c/a\u003e.NET 9\nPackage name | Affected version | Patched version\n------------ | ---------------- | -------------------------\n[Microsoft.WindowsDesktop.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-arm64)               | \u003e= 9.0.0, \u003c= 9.0.15 | 9.0.16\n[MMicrosoft.WindowsDesktop.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x64)                  | \u003e= 9.0.0, \u003c= 9.0.15 | 9.0.16\n[Microsoft.WindowsDesktop.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x86)                   | \u003e= 9.0.0, \u003c= 9.0.15 | 9.0.16\n\n### \u003ca name=\".NET 8\"\u003e\u003c/a\u003e.NET 8\nPackage name | Affected version | Patched version\n------------ | ---------------- | -------------------------\n[Microsoft.WindowsDesktop.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-arm64)               | \u003e= 8.0.0, \u003c= 8.0.26 | 8.0.27\n[MMicrosoft.WindowsDesktop.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x64)                  | \u003e= 8.0.0, \u003c= 8.0.26 | 8.0.27\n[Microsoft.WindowsDesktop.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x86)                   | \u003e= 8.0.0, \u003c= 8.0.26 | 8.0.27\n\n## Advisory FAQ\n\n### \u003ca name=\"how-affected\"\u003e\u003c/a\u003eHow do I know if I am affected?\n\nIf using a package listed in [affected packages](#affected-packages), an application is exposed to the vulnerability.\n\n### \u003ca name=\"how-fix\"\u003e\u003c/a\u003eHow do I fix the issue?\n\n1. 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\u0027s .NET  SDKs.\n2. If a developer\u0027s 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. \n\nOnce developers have installed the updated runtime or SDK, they can restart the app for the update to take effect.\n\nAdditionally, if developers have deployed [self-contained applications](https://docs.microsoft.com/dotnet/core/deploying/#self-contained-deployments-scd) targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.\n\n## Other Information\n\n### Reporting Security Issues\n\nA 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](https://msrc.microsoft.com/report/vulnerability/new). Further information can be found in the MSRC [Report an Issue FAQ](https://www.microsoft.com/msrc/faqs-report-an-issue).\n\nSecurity 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.\n\n### Support\n\nQuestions 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.\n\n### Disclaimer\n\nThe 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.\n\n### External Links\n\n[CVE-2026-35433]( https://www.cve.org/CVERecord?id=CVE-2026-35433)\n\n### Acknowledgements\n\nKy0toFu\n\n### Revisions\n\nV1.0 (May 12, 2026): Advisory published.",
  "id": "GHSA-8x9c-mqxv-q2pp",
  "modified": "2026-05-18T19:20:20Z",
  "published": "2026-05-18T19:20:19Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/dotnet/wpf/security/advisories/GHSA-8x9c-mqxv-q2pp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-35433"
    },
    {
      "type": "WEB",
      "url": "https://github.com/dotnet/announcements/issues/398"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/dotnet/wpf"
    },
    {
      "type": "WEB",
      "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-35433"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Microsoft Security Advisory CVE-2026-35433 \u2013 .NET Elevation of Privilege Vulnerability "
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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