Critical

Semantic Kernel has Arbitrary File Write via AI Agent Function Calling in .NET SDK

  • Disclosed: 06.02.2026
  • Updated: 11.10.2026 13:17

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. 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 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?

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
.NET (NuGet) Microsoft.SemanticKernel.Core < 1.71.0 1.71.0
Python (PyPI) semantic-kernel < 1.39.3 1.39.3

References

CVSS score 9.9/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Weakness (CWE)
CWE-22
Platform
.NET (NuGet), Python (PyPI)
Package
Microsoft.SemanticKernel.Core, semantic-kernel
Disclosed
06.02.2026
Updated
11.10.2026 13:17

Sources and licenses

OSV / GitHub Advisory Database - GHSA-2ww3-72rp-wpp4 - CC BY 4.0

OSV / GitHub Advisory Database - PYSEC-2026-531 - PyPA Advisory Database; CC BY 4.0

Vulnerability history: semantic-kernel

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
2
First → latest
02.2026 02.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 2

Disclosures per year

  1. 2026: 2
  1. Semantic Kernel has Arbitrary File Write via AI Agent Function Calling in .NET SDK this entry
    Critical · 9.9 CVE-2026-25592 < 1.39.3 1.39.3

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