CVE-2025-26646 .NET, Visual Studio, and Build Tools for Visual Studio Spoofing Vulnerability
High 8.0
Published
Updated
Check this codebase for CVE-2025-26646 and fix it if it is affected.
What it is: CVE-2025-26646 is a high-severity path traversal vulnerability in Microsoft .Net, published on 13 May 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-26646 in the wild and no public exploit code.
Affected packages and fixed versions:
- Microsoft.Build.Tasks.Core (NuGet): affected from 15.8.166; fixed in 15.9.30
- Microsoft.Build.Tasks.Core (NuGet): affected from 15.8.166; fixed in 15.9.30
- Microsoft.Build.Tasks.Core (NuGet): affected from 16.0.461; fixed in 16.11.6
- Microsoft.Build.Tasks.Core (NuGet): affected from 16.0.461; fixed in 16.11.6
- Microsoft.Build.Tasks.Core (NuGet): affected from 17.0.0; fixed in 17.8.29
- Microsoft.Build.Tasks.Core (NuGet): affected from 17.0.0; fixed in 17.8.29
- Microsoft.Build.Tasks.Core (NuGet): affected from 17.11.4; fixed in 17.12.36
- Microsoft.Build.Tasks.Core (NuGet): affected from 17.11.4; fixed in 17.12.36
- Microsoft.Build.Tasks.Core (NuGet): affected from 17.12.6; fixed in 17.13.26
- Microsoft.Build.Tasks.Core (NuGet): affected from 17.12.6; fixed in 17.13.26
- Microsoft.Build.Tasks.Core (NuGet): affected from 17.13.9; fixed in 17.14.8
- Microsoft.Build.Tasks.Core (NuGet): affected from 17.13.9; fixed in 17.14.8
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2025-26646/ (Markdown: https://insights.sbomify.com/CVE-2025-26646/index.md)
An authorized attacker can exploit external control of file names or paths in .NET and Visual Studio to perform spoofing over a network.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-26646?
CVE-2025-26646 is a high-severity path traversal vulnerability in Microsoft .Net, published on 13 May 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-73
Which versions are affected by CVE-2025-26646?
16 open source packages ship an affected version, including Microsoft.Build.Tasks.Core, dotnet and dotnet-sdk. It affects 3 products.
| Package | Affected | Fixed in |
|---|---|---|
Microsoft.Build.Tasks.Core NuGet | From 15.8.166 | 15.9.30 |
Microsoft.Build.Tasks.Core NuGet | From 15.8.166 | 15.9.30 |
Microsoft.Build.Tasks.Core NuGet | From 16.0.461 | 16.11.6 |
Microsoft.Build.Tasks.Core NuGet | From 16.0.461 | 16.11.6 |
Microsoft.Build.Tasks.Core NuGet | From 17.0.0 | 17.8.29 |
Microsoft.Build.Tasks.Core NuGet | From 17.0.0 | 17.8.29 |
10 more packages
Microsoft.Build.Tasks.Core NuGet | From 17.11.4 | 17.12.36 |
Microsoft.Build.Tasks.Core NuGet | From 17.11.4 | 17.12.36 |
Microsoft.Build.Tasks.Core NuGet | From 17.12.6 | 17.13.26 |
Microsoft.Build.Tasks.Core NuGet | From 17.12.6 | 17.13.26 |
Microsoft.Build.Tasks.Core NuGet | From 17.13.9 | 17.14.8 |
Microsoft.Build.Tasks.Core NuGet | From 17.13.9 | 17.14.8 |
Microsoft.Build.Tasks.Core NuGet | From 17.9.5 | 17.10.29 |
Microsoft.Build.Tasks.Core NuGet | From 17.9.5 | 17.10.29 |
dotnet Bitnami | From 8.0.0 | 8.0.16, 9.0.5 |
dotnet-sdk Bitnami | From 8.0.0 | 8.0.101, 9.0.100 |
Linux distribution packages (24)
aspnetcore-runtime-8.0 AlmaLinux:10 | All versions | 8.0.16-1.el10_0 |
aspnetcore-runtime-9.0 AlmaLinux:10 | All versions | 9.0.5-1.el10_0 |
aspnetcore-runtime-dbg-8.0 AlmaLinux:10 | All versions | 8.0.16-1.el10_0 |
aspnetcore-runtime-dbg-9.0 AlmaLinux:10 | All versions | 9.0.5-1.el10_0 |
aspnetcore-targeting-pack-8.0 AlmaLinux:10 | All versions | 8.0.16-1.el10_0 |
aspnetcore-targeting-pack-9.0 AlmaLinux:10 | All versions | 9.0.5-1.el10_0 |
dotnet-apphost-pack-8.0 AlmaLinux:10 | All versions | 8.0.16-1.el10_0 |
dotnet-apphost-pack-9.0 AlmaLinux:10 | All versions | 9.0.5-1.el10_0 |
dotnet-host AlmaLinux:10 | All versions | 9.0.5-1.el10_0 |
dotnet-hostfxr-8.0 AlmaLinux:10 | All versions | 8.0.16-1.el10_0 |
dotnet-hostfxr-9.0 AlmaLinux:10 | All versions | 9.0.5-1.el10_0 |
dotnet-runtime-8.0 AlmaLinux:10 | All versions | 8.0.16-1.el10_0 |
dotnet-runtime-9.0 AlmaLinux:10 | All versions | 9.0.5-1.el10_0 |
dotnet-runtime-dbg-8.0 AlmaLinux:10 | All versions | 8.0.16-1.el10_0 |
dotnet-runtime-dbg-9.0 AlmaLinux:10 | All versions | 9.0.5-1.el10_0 |
dotnet-sdk-8.0 AlmaLinux:10 | All versions | 8.0.116-1.el10_0 |
dotnet-sdk-8.0-source-built-artifacts AlmaLinux:10 | All versions | 8.0.116-1.el10_0 |
dotnet-sdk-9.0 AlmaLinux:10 | All versions | 9.0.106-1.el10_0 |
dotnet-sdk-9.0-source-built-artifacts AlmaLinux:10 | All versions | 9.0.106-1.el10_0 |
dotnet-sdk-aot-9.0 AlmaLinux:10 | All versions | 9.0.106-1.el10_0 |
dotnet-sdk-dbg-8.0 AlmaLinux:10 | All versions | 8.0.116-1.el10_0 |
dotnet-sdk-dbg-9.0 AlmaLinux:10 | All versions | 9.0.106-1.el10_0 |
dotnet-targeting-pack-8.0 AlmaLinux:10 | All versions | 8.0.16-1.el10_0 |
dotnet-targeting-pack-9.0 AlmaLinux:10 | All versions | 9.0.5-1.el10_0 |
Products include Microsoft .Net, Microsoft Build Tools, Microsoft Visual Studio 2022.
How do I fix CVE-2025-26646?
Upgrade Microsoft.Build.Tasks.Core to a fixed version for your release line: 15.9.30, 16.11.6, 17.8.29 or 17.12.36.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2025-26646 being exploited?
There is no known exploitation of CVE-2025-26646 in the wild and no public exploit code.
Other vulnerabilities in Microsoft .Net
- CVE-2024-43498 .NET and Visual Studio Remote Code Execution Vulnerability
- CVE-2024-0057 NET, .NET Framework, and Visual Studio Security Feature Bypass Vulnerability
- CVE-2026-96957 .NET Security Feature Bypass Vulnerability
- CVE-2026-69439 .NET and Visual Studio Elevation of Privilege Vulnerability
- CVE-2026-71328 .NET and Visual Studio Remote Code Execution Vulnerability
Sources
Also known as ALSA-2025:7571, ALSA-2025:7589, ALSA-2025:7598, ALSA-2025:7599, ALSA-2025:7600, ALSA-2025:7601 and 23 more.