.NET, Visual Studio, and Build Tools for Visual Studio Spoofing Vulnerability

CISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.

External control of file name or path in .NET, Visual Studio, and Build Tools for Visual Studio allows an authorized attacker to perform spoofing over a network.

Source published

13 May 2025 21:39:52 UTC

Source modified

26 Feb 2026 18:28:10 UTC

Saved here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · 8.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

External control of file name or path in .NET, Visual Studio, and Build Tools for Visual Studio allows an authorized attacker to perform spoofing over a network.

Source published

May 13, 2025, 9:39:52 PM (timezone not stated)

Source modified

Feb 26, 2026, 6:28:10 PM (timezone not stated)

Saved here

15 Nov 2026 03:39:23 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 3.1 · 8.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

External control of file name or path in .NET, Visual Studio, and Build Tools for Visual Studio allows an authorized attacker to perform spoofing over a network.

Source published

13 May 2025 22:15:20 UTC

Source modified

17 Jun 2026 09:02:11 UTC

Saved here

25 Oct 2026 02:24:42 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · [email protected] · Secondary · 8.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

# Microsoft Security Advisory CVE-2025-26646: .NET Spoofing Vulnerability ## <a name="executive-summary"></a>Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 9.0.xxx and .NET 8.0.xxx SDK. This advisory also provides guidance on what developers can do to update their applications to address this vulnerability. A vulnerability exists in .NET SDK or MSBuild applications where external control of file name or path allows an unauthorized attacked to perform spoofing over a network. ## Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/356 ### <a name="mitigation-factors"></a>Mitigation factors Projects which do not utilize the [DownloadFile](https://learn.microsoft.com/visualstudio/msbuild/downloadfile-task) build task are not susceptible to this vulnerability. ## <a name="affected-software"></a>Affected software * Any installation of .NET 9.0.105 SDK, .NET 9.0.203 SDK or earlier. * Any installation of .NET 8.0.115 SDK, .NET 8.0.311 or .NET 8.0.312 SDK, .NET 8.0.408 or .NET 8.0.409 SDK or earlier. ## <a name="affected-packages"></a>Affected Packages The vulnerability affects any Microsoft .NET Core project if it uses any of affected packages versions listed below Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- [Microsoft.Build.Tasks.Core](https://www.nuget.org/packages/Microsoft.Build.Tasks.Core) |>= 15.8.166, <=15.9.20<br />>=16.0.461, <= 16.11.0<br />>= 17.0.0, <= 17.8.3<br/>>= 17.9.5, <= 17.10.4<br />17.11.4<br />17.12.6 <br />17.13.9 | 15.9.30<br />16.11.6<br />17.8.29<br/>17.10.29<br />17.12.36<br />17.13.26 <br />17.14.8 ## Advisory FAQ ### <a name="how-affected"></a>How do I know if I am affected? If you have a .NET SDK with a version listed, or an affected package listed in [affected software](#affected-packages) or [affected packages](#affected-software), 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 9.0 SDK or .NET 8.0 SDK. 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. You will see output like the following; ``` .NET SDK: Version: 9.0.100 Commit: 59db016f11 Workload version: 9.0.100-manifests.3068a692 MSBuild version: 17.12.7+5b8665660 Runtime Environment: OS Name: Mac OS X OS Version: 15.2 OS Platform: Darwin RID: osx-arm64 Base Path: /usr/local/share/dotnet/sdk/9.0.100/ .NET workloads installed: There are no installed workloads to display. Configured to use loose manifests when installing new manifests. Host: Version: 9.0.0 Architecture: arm64 Commit: 9d5a6a9aa4 .NET SDKs installed: 9.0.100 [/usr/local/share/dotnet/sdk] .NET runtimes installed: Microsoft.AspNetCore.App 9.0.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App] Microsoft.NETCore.App 9.0.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App] Other architectures found: x64 [/usr/local/share/dotnet] registered at [/etc/dotnet/install_location_x64] Environment variables: Not set global.json file: Not found Learn more: https://aka.ms/dotnet/info Download .NET: https://aka.ms/dotnet/download ``` * If you're using .NET 9.0, you should download and install the appropriate SDK: `.NET 9.0.300` for Visual Studio 2022 v17.14, `.NET 9.0.204` for v17.13, or `.NET 9.0.106` for v17.12. Download from https://dotnet.microsoft.com/download/dotnet-core/9.0. * If you're using .NET 8.0, you should download and install the appropriate SDK: `.NET 8.0.410` for Visual Studio 2022 v17.11, `.NET 8.0.313` for v17.10, or `.NET 8.0.116` for v17.8. Download from https://dotnet.microsoft.com/download/dotnet-core/8.0. Once you have installed the updated SDK, restart your apps for the update to take effect. ## Other Information ### Reporting Security Issues If you have found a potential security issue in .NET 8.0 or .NET 9.0, please email details to [email protected]. Reports may qualify for the Microsoft .NET Core & .NET 5 Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at <https://aka.ms/corebounty>. ### Support You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/aspnetcore. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue. ### Disclaimer The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Source published

13 May 2025 21:38:50 UTC

Source modified

10 Sep 2026 03:50:58 UTC

Saved here

23 Oct 2026 16:01:25 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

Publisher rating · HIGH