CVE-2026-87697

Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code over a network.

Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code over a network.

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.

WPF XPS synthetic hyperlinks exposed through UI Automation can bypass restrictive navigation checks and reach attacker-controlled content, enabling remote code execution after user interaction.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/471

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"></a>Affected Packages

The vulnerability affects Microsoft .NET projects that use an affected package version listed below.

Package name | Affected version | Patched version ------------ | ---------------- | --------------- Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 9.0.0, <= 9.0.20 | 9.0.21 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 9.0.0, <= 9.0.20 | 9.0.21 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 9.0.0, <= 9.0.20 | 9.0.21 Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 8.0.0, <= 8.0.31 | 8.0.32 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 8.0.0, <= 8.0.31 | 8.0.32 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 8.0.0, <= 8.0.31 | 8.0.32 Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 10.0.0, <= 10.0.12 | 10.0.13 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 10.0.0, <= 10.0.12 | 10.0.13 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 10.0.0, <= 10.0.12 | 10.0.13

Advisory FAQ

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

If using a package listed in affected packages, you're 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. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs.
2. If your application references the vulnerable package, update the package reference to the patched version. You can list the versions you have installed by running the dotnet --info command.

Once you have installed the updated runtime or SDK, restart your apps for the update to take effect.

Additionally, if you've deployed self-contained applications targeting any of the…

Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code over a network.

Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code over a network.

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.

WPF XPS synthetic hyperlinks exposed through UI Automation can bypass restrictive navigation checks and reach attacker-controlled content, enabling remote code execution after user interaction.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/471

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"></a>Affected Packages

The vulnerability affects Microsoft .NET projects that use an affected package version listed below.

Package name | Affected version | Patched version ------------ | ---------------- | --------------- Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 9.0.0, <= 9.0.20 | 9.0.21 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 9.0.0, <= 9.0.20 | 9.0.21 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 9.0.0, <= 9.0.20 | 9.0.21 Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 8.0.0, <= 8.0.31 | 8.0.32 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 8.0.0, <= 8.0.31 | 8.0.32 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 8.0.0, <= 8.0.31 | 8.0.32 Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 10.0.0, <= 10.0.12 | 10.0.13 Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 10.0.0, <= 10.0.12 | 10.0.13 Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 10.0.0, <= 10.0.12 | 10.0.13

Advisory FAQ

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

If using a package listed in affected packages, you're 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. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs.
2. If your application references the vulnerable package, update the package reference to the patched version. You can list the versions you have installed by running the dotnet --info command.

Once you have installed the updated runtime or SDK, restart your apps for the update to take effect.

Additionally, if you've deployed self-contained applications targeting any of the…

Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code over a network.