Microsoft Security Advisory CVE-2026-32175 – .NET Core Tampering Vulnerability
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.
A tampering vulnerability exists when .NET Core improperly handles specially crafted files. An attacker who successfully exploited this vulnerability could write arbitrary files and directories to certain locations on a vulnerable system. However, an attacker would have limited control over the destination of the files and directories.
To exploit the vulnerability, an attacker must send a specially crafted file to a vulnerable system.
The security update fixes the vulnerability by ensuring .NET Core properly handles files.
Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/396
CVSS Details
- Version: 3.1
- Severity:
- Score: 4.3
- Vector: /AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- Weakness: CWE-36: Absolute Path Traversal
Affected Platforms
- Platforms: Windows
- Architectures: All
<a name="affected-packages"></a>Affected Packages
The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below
<a name=".NET 10"></a>.NET 10
Package name | Affected version | Patched version
------------ | ---------------- | -------------------------
[Microsoft.NetCore.App.Runtime.win-arm](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-arm) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.NetCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-arm64) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.NetCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-x64) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.NetCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-x86) | >= 10.0.0, <= 10.0.7 | 10.0.8
<a name=".NET 9"></a>.NET 9
Package name | Affected version | Patched version
------------ | ---------------- | -------------------------
[Microsoft.NetCore.App.Runtime.win-arm](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-arm) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.NetCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-arm64) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.NetCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-x64) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.NetCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-x86) | >= 9.0.0, <= 9.0.15 | 9.0.16
<a name=".NET 8"></a>.NET 8
Package name | Affected version | Patched version
------------ | ---------------- | -------------------------
[Microsoft.NetCore.App.Runtime.win-arm](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-arm) | >= 8.0.0, <= 8.0.26 | 8.0.27
[Microsoft.NetCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-arm64) | >= 8.0.0, <= 8.0.26 | 8.0.27
[Microsoft.NetCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-x64) | >= 8.0.0, <= 8.0.26 | 8.0.27
[Microsoft.NetCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.NetCore.App.Runtime.win-x86) | >= 8.0.0, <= 8.0.26 | 8.0.27
Advisory FAQ
<a name="how-affected"></a>How do I know if I am affected?
If using a package listed in [affected packages](#affected-packages), a developer's application is 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 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 their .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 their apps for the update to take effect.
Additionally, if they've 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.
Other Information
Reporting Security Issues
If someone has found a potential security issue in a
