Microsoft.WindowsDesktop.App.Runtime.win-arm64 Fixes High-Severity Bug CVE-2026-83520

Maintainers of Microsoft.WindowsDesktop.App.Runtime.win-arm64, a package in the nuget ecosystem, have published a high-severity security advisory (CVE-2026-83520): Microsoft Security Advisory CVE-2026-83520 - .NET and Visual Studio Remote Code Execution Vulnerability.

At a glance

Advisory

GHSA-4w5f-7jp2-w48g

CVE

CVE-2026-83520

Package

Microsoft.WindowsDesktop.App.Runtime.win-arm64 (nuget)

Severity

High

Patched in

11.0.0-rc.2

What is the issue?

The GitHub-reviewed advisory explains: 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

Affected versions

The advisory lists a CVSS score of 8.8.

How to fix it

• Upgrade the affected package to the first patched version listed above.
• Rebuild and redeploy applications that bundle the vulnerable dependency.
• Run your dependency scanner (npm audit, pip-audit, Dependabot) to find transitive uses.
• Review the advisory references for workaround details if you cannot upgrade yet.

What to do and how to stay safe: CVE-2026-83520

• Vulnerability severity scores ignore your specific architecture and context.
• Exploitability depends on network exposure and user behavior, not just code flaws.
• Prioritization requires continuous asset inventory and threat intelligence alignment.

Risk-based vulnerability management focuses your limited resources on the flaws that actually threaten your business. Start by mapping your critical assets and checking for active exploits to prioritize your backlog.

Step-by-step guide: Risk-Based Vulnerability Management: Prioritize Fixes by Actual Danger

General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.

Frequently asked questions

What is CVE-2026-83520?

CVE-2026-83520 is a security vulnerability in Microsoft.WindowsDesktop.App.Runtime.win-arm64 (nuget).

Which version fixes CVE-2026-83520?

The fix is in version 11.0.0-rc.2.