Microsoft Security Advisory CVE-2026-50650 – .NET Elevation of Privilege Vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.8 · CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

• CVE-2026-50650: 0.46% estimated exploitation activity in the next 30 days; percentile 40.06 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in Windows Presentation Foundation (WPF). This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. An elevation of privilege vulnerability exists in Windows Presentation Foundation (WPF) in .NET 8, .NET 9, and .NET 10 when parsing specially crafted XAML input. An attacker who successfully exploits this vulnerability could elevate privileges on the affected system.

Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/421

CVSS Details - Version: 3.1 - Severity: High - Score: 7.8 - Vector: `CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H` - Weakness: CWE-94 (Improper Control of Generation of Code ('Code Injection'))

Affected Platforms - Platforms: Windows - Architectures: All

Affected Packages The vulnerability affects any…

Published by the source

21 Jul 2026, 16:06 UTC

Last modified by the source

4 Nov 2026, 04:15 UTC

Source last checked

4 Nov 2026, 06:40 UTC

1. Revision 3 · amended · 4 Nov 2026

   Amended from osv record GHSA-2969-4q4w-w5h3

2. Revision 2 · amended · 4 Nov 2026

   Amended from ghsa record GHSA-2969-4q4w-w5h3

3. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-2969-4q4w-w5h3

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# Patch Next advisory brief: CVE-2026-50650

Advisory: Microsoft Security Advisory CVE-2026-50650 – .NET Elevation of Privilege Vulnerability
IDs: CVE-2026-50650, GHSA-2969-4q4w-w5h3
Record: https://patchnext.com/advisories/cve-2026-50650 (revision 3, source checked 4 Nov 2026, 06:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: microsoft.windowsdesktop.app.runtime.win-x86 10.0.10, 9.0.18, 8.0.29; microsoft.windowsdesktop.app.runtime.win-arm64 10.0.10, 9.0.18, 8.0.29; microsoft.windowsdesktop.app.runtime.win-x64 10.0.10, 9.0.18, 8.0.29. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet microsoft.windowsdesktop.app.runtime.win-x86: affected >= 10.0.0, < 10.0.10; >= 9.0.0, < 9.0.18; >= 8.0.0, < 8.0.29; fixed in 8.0.29, 10.0.10, 9.0.18
- NuGet microsoft.windowsdesktop.app.runtime.win-arm64: affected >= 10.0.0, < 10.0.10; >= 9.0.0, < 9.0.18; >= 8.0.0, < 8.0.29; fixed in 8.0.29, 10.0.10, 9.0.18
- NuGet microsoft.windowsdesktop.app.runtime.win-x64: affected >= 10.0.0, < 10.0.10; >= 9.0.0, < 9.0.18; >= 8.0.0, < 8.0.29; fixed in 8.0.29, 10.0.10, 9.0.18

## Suggested inspection (read-only)
- NuGet microsoft.windowsdesktop.app.runtime.win-x86: check the installed version with your package manager.
- NuGet microsoft.windowsdesktop.app.runtime.win-arm64: check the installed version with your package manager.
- NuGet microsoft.windowsdesktop.app.runtime.win-x64: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on microsoft.windowsdesktop.app.runtime.win-x86, microsoft.windowsdesktop.app.runtime.win-arm64, microsoft.windowsdesktop.app.runtime.win-x64.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-2969-4q4w-w5h3 (GitHub-reviewed advisory GHSA-2969-4q4w-w5h3 lists affected ranges: NuGet microsoft.windowsdesktop.app.runtime.win-x64 >=10.0.0 =9.0.0 =8.0.0 =10.0.0 =9.0.0 =8.0.0 =10.0.0 =9.0.0 =8.0.0 <=8.0.28)
- Verified: https://osv.dev/vulnerability/GHSA-2969-4q4w-w5h3 (OSV record GHSA-2969-4q4w-w5h3 lists affected ranges: NuGet microsoft.windowsdesktop.app.runtime.win-x64 >=10.0.0 =9.0.0 =8.0.0 =10.0.0 =9.0.0 =8.0.0 =10.0.0 =9.0.0 =8.0.0 <8.0.29 (fixed))

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