Yes. A NuGet package is more than a library. It can include MSBuild props and targets files, analyzers and other assets that take part in your build, which means a package you add can influence what the build does on your machine or CI agent. You control this with asset metadata, review and clean build agents.
What a package can contribute
Microsoft's PackageReference documentation lists the asset types a package may carry and that your project can include or exclude.
| Asset | What it is |
|---|---|
| compile | Assemblies in the lib folder you compile against |
| runtime | Assemblies copied to the build output |
| contentFiles | Files in the contentfiles folder |
| build | Props and targets files in the build folder |
| buildMultitargeting | Props and targets for cross framework targeting |
| buildTransitive | Props and targets that flow transitively to consuming projects |
| analyzers | .NET analyzers |
| native | Native binaries |
The build, buildMultitargeting and buildTransitive items are MSBuild files. They become part of how your project builds, not only what it references.
Why this matters for security
An ordinary dependency review looks at the code your application calls. Build assets act earlier, while compiling and packaging. A malicious or compromised package could abuse that stage. The build stage is part of the same trust decision as the library code. Treat any package that ships build assets as having a wider reach than a plain library.
Also note the default flow. For PrivateAssets, the documented default is contentfiles, analyzers and build. Because build is in that default list, props and targets from a package are kept private to the referencing project unless you change the metadata. If a package is itself packed into another package, what you expose depends on this setting.
How to limit exposure
- Prefer packages that need no build assets for simple libraries.
- Mark development only tools with PrivateAssets set to all, so they do not flow to your consumers.
- Use ExcludeAssets for asset types you do not want, for example build.
- Read the package contents before first use, since a nupkg is a zip archive.
- Restrict who can add dependencies by reviewing changes to project files and Directory.Packages.props.
- Run builds on clean, short lived agents, and keep secrets out of the build environment where possible.
<PackageReference Include="Contoso.BuildTool" Version="1.4.0">
<PrivateAssets>all</PrivateAssets>
<IncludeAssets>runtime; build; analyzers</IncludeAssets>
</PackageReference>
Where analyzers fit
Analyzers run inside the compiler. That is useful for catching issues, but it means they are code you trust at build time. The built in .NET analyzers ship with the SDK. Third party analyzers arrive as packages and deserve the same review as any dependency.
A review habit
When a pull request adds or updates a package, check three things: who publishes it, whether it carries build, analyzers or tools folders, and whether the version changed more than expected. Ask for a short note on why it is needed.
Try it yourself
Click through it at your own pace, or open it full screen. Use it to see how many packages sit behind your direct references, each with its own assets.
Safeguard's dependency scanning and SBOM output give you the inventory to review, and a free scan is a quick way to get one.
Quick check
Do I need to worry about build assets from well known packages?
Apply the same review to every package, but focus more where a package ships build or analyzer assets, or where its maintainers recently changed.
What does PrivateAssets all do?
It keeps the package's assets from flowing to projects that consume your project or package.
Sources
- NuGet PackageReference in project files, Microsoft Learn
- Best practices for a secure software supply chain, Microsoft Learn
Last reviewed: 19 October 2026.
