Advisoriesby IbisSemantic Kernel has Arbitrary File Write via AI Agent Function Calling in .NET SDK
Impact
_What kind of vulnerability is it? Who is impacted?_
An Arbitrary File Write vulnerability has been identified in Microsoft's Semantic Kernel .NET SDK, specifically within the SessionsPythonPlugin.
Developers who have built applications which include Microsoft's Semantic Kernel .NET SDK and are using the SessionsPythonPlugin
Patches
_Has the problem been patched? What versions should users upgrade to?_
The problem has been fixed in [Microsoft.SemanticKernel.Plugins.Core version 1.71.0](https://www.nuget.org/packages/Microsoft.SemanticKernel.Plugins.Core/1.71.0). Users should upgrade to version 1.71.0 or higher.
Workarounds
_Is there a way for users to fix or remediate the vulnerability without upgrading?_
Users can create a [Function Invocation Filter](https://learn.microsoft.com/en-us/semantic-kernel/concepts/enterprise-readiness/filters?pivots=programming-language-csharp#function-invocation-filter) which checks the arguments being passed to any calls to DownloadFileAsync or UploadFileAsync and ensures the provided localFilePath is allow listed.
References
_Are there any links users can visit to find out more?_
- [Sample showing safe use of the CodeInterpreterPlugin](https://github.com/microsoft/semantic-kernel/blob/main/dotnet/samples/Demos/CodeInterpreterPlugin/Program.cs#L61-L64)
- [PR to Add file upload security controls to...
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| semantic-kernel PyPI | < 1.39.3 | 1.39.3 |
Details and references
### Impact _What kind of vulnerability is it? Who is impacted?_ An Arbitrary File Write vulnerability has been identified in Microsoft's Semantic Kernel .NET SDK, specifically within the `SessionsPythonPlugin`. Developers who have built applications which include Microsoft's Semantic Kernel .NET SDK and are using the `SessionsPythonPlugin` ### Patches _Has the problem been patched? What versions should users upgrade to?_ The problem has been fixed in [Microsoft.SemanticKernel.Plugins.Core version 1.71.0](https://www.nuget.org/packages/Microsoft.SemanticKernel.Plugins.Core/1.71.0). Users should upgrade to version 1.71.0 or higher. ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ Users can create a [Function Invocation Filter](https://learn.microsoft.com/en-us/semantic-kernel/concepts/enterprise-readiness/filters?pivots=programming-language-csharp#function-invocation-filter) which checks the arguments being passed to any calls to `DownloadFileAsync ` or `UploadFileAsync` and ensures the provided `localFilePath` is allow listed. ### References _Are there any links users can visit to find out more?_ - [Sample showing safe use of the CodeInterpreterPlugin](https://github.com/microsoft/semantic-kernel/blob/main/dotnet/samples/Demos/CodeInterpreterPlugin/Program.cs#L61-L64) - [PR to Add file upload security controls to SessionsPythonPlugin](https://github.com/microsoft/semantic-kernel/pull/13478/changes#diff-88d3cacba2bfa84eef8f2aa171b34f9940338cbb784a3ffc49f5fe3af1b8943d)
- CVSS 3.1
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Severity from
- GitHub (reviewed advisory)
- Weakness
- CWE-22
- Also known as
- CVE-2026-25592, PYSEC-2026-531
- github.com/microsoft/semantic-kernel/security/advisories/GHSA-2ww3-72rp-wpp4
- nvd.nist.gov/vuln/detail/CVE-2026-25592
- github.com/microsoft/semantic-kernel/pull/13478/changes#diff-88d3cacba2bfa84eef8f2aa171b34f9940338cbb784a3ffc49f5fe3af1b8943d
- github.com/microsoft/semantic-kernel
- github.com/microsoft/semantic-kernel/blob/main/dotnet/samples/Demos/CodeInterpreterPlugin/Program.cs#L61-L64