Is CVE-2026-70035 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-70035 being exploited in the wild.

How severe is CVE-2026-70035?

High severity, with a CVSS score of 8.8, published 13 October 2026.

Is there a fix for CVE-2026-70035?

Yes. Microsoft.WindowsDesktop.App.Runtime.win-arm64 (NuGet): upgrade to 10.0.13 or later; Microsoft.WindowsDesktop.App.Runtime.win-x64 (NuGet): upgrade to 10.0.13 or later; Microsoft.WindowsDesktop.App.Runtime.win-x86 (NuGet): upgrade to 10.0.13 or later. Until then: Update to the patched .NET runtime versions. If you have deployed self-contained applications targeting the affected versions, recompile and redeploy them with the updated runtime. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-70035 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-70035?

Check whether you run Microsoft .Net, Microsoft.WindowsDesktop.App.Runtime.win-arm64 (NuGet), Microsoft.WindowsDesktop.App.Runtime.win-x64 (NuGet) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-70035: .NET WindowsDesktop.App.Runtime deserialization remote code execution

CVE-2026-70035 · Severity: high · CVSS 8.8 · Published 2026-10-13

Microsoft .NET's Windows Desktop runtime (WPF), used to build desktop applications on Windows, contains a deserialization flaw that allows attackers to execute arbitrary code when an application processes maliciously crafted XAML or XPS content. An attacker can trigger this vulnerability through user interaction, such as opening a specially crafted file or clicking a malicious link, leading to complete system compromise with the privileges of the affected application.

Technologies: Microsoft .Net, Microsoft.WindowsDesktop.App.Runtime.win-arm64 (NuGet), Microsoft.WindowsDesktop.App.Runtime.win-x64 (NuGet), Microsoft.WindowsDesktop.App.Runtime.win-x86 (NuGet). Vendors: Microsoft, NuGet.

Quick answers

Is CVE-2026-70035 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-70035 being exploited in the wild.
How severe is CVE-2026-70035?: High severity, with a CVSS score of 8.8, published 13 October 2026.
Which products and versions are affected?: Microsoft .Net 8.0.0–8.0.31, 9.0.0–9.0.20, 10.0.0–10.0.12, 11.0.0-preview.1–11.0.0-rc.1; Microsoft.WindowsDesktop.App.Runtime.win-arm64 (NuGet) >= 10.0.0, <= 10.0.12, ECOSYSTEM:introduced=10.0.0,fixed=10.0.13; Microsoft.WindowsDesktop.App.Runtime.win-x64 (NuGet) >= 10.0.0, <= 10.0.12, ECOSYSTEM:introduced=10.0.0,fixed=10.0.13; Microsoft.WindowsDesktop.App.Runtime.win-x86 (NuGet) >= 10.0.0, <= 10.0.12, ECOSYSTEM:introduced=10.0.0,fixed=10.0.13.
Is there a fix for CVE-2026-70035?: Yes. Microsoft.WindowsDesktop.App.Runtime.win-arm64 (NuGet): upgrade to 10.0.13 or later; Microsoft.WindowsDesktop.App.Runtime.win-x64 (NuGet): upgrade to 10.0.13 or later; Microsoft.WindowsDesktop.App.Runtime.win-x86 (NuGet): upgrade to 10.0.13 or later. Until then: Update to the patched .NET runtime versions. If you have deployed self-contained applications targeting the affected versions, recompile and redeploy them with the updated runtime. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-70035 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-70035?: Check whether you run Microsoft .Net, Microsoft.WindowsDesktop.App.Runtime.win-arm64 (NuGet), Microsoft.WindowsDesktop.App.Runtime.win-x64 (NuGet) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Microsoft.WindowsDesktop.App.Runtime.win-arm64 (NuGet): upgrade to 10.0.13 or later

dotnet add package Microsoft.WindowsDesktop.App.Runtime.win-arm64 --version 10.0.13

Microsoft.WindowsDesktop.App.Runtime.win-x64 (NuGet): upgrade to 10.0.13 or later

dotnet add package Microsoft.WindowsDesktop.App.Runtime.win-x64 --version 10.0.13

Microsoft.WindowsDesktop.App.Runtime.win-x86 (NuGet): upgrade to 10.0.13 or later

dotnet add package Microsoft.WindowsDesktop.App.Runtime.win-x86 --version 10.0.13

Update to the patched .NET runtime versions. If you have deployed self-contained applications targeting the affected versions, recompile and redeploy them with the updated runtime.

Technical details

The vulnerability is a deserialization flaw (CWE-502) in Microsoft.WindowsDesktop.App.Runtime that allows remote code execution through unsafe XAML processing and URI handling. The attack requires network access and user interaction (opening a file or clicking a hyperlink). The fix restricts XAML parsing, adds nesting-depth limits, and hardens URI fetching and font handling to prevent untrusted content from being executed.

Affected products

Microsoft .NET 8.0.0–8.0.31, 9.0.0–9.0.20, 10.0.0–10.0.12, 11.0.0-preview.1–11.0.0-rc.1

Identifiers

CVE-2026-70035
GHSA-4j9v-h7pp-725h

Timeline

2026-10-13: disclosed

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