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CVE-2026-25592 — Vulnerability in Microsoft.SemanticKernel.Core —...

CRITICAL

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

Published February 6, 2026Updated June 29, 2026Source: osv

Summary

### 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)

Advisory Timeline

  • First published February 6, 2026 (248 days ago).
  • Last revised June 29, 2026 — 143 days after initial publication.

Remediation

Upgrade to the fixed version using your package manager.

NuGet
Update Microsoft.SemanticKernel.Core to 1.71.0 or later
dotnet add package Microsoft.SemanticKernel.Core --version 1.71.0
pip
Update semantic-kernel to 1.39.3 or later
pip install "semantic-kernel>=1.39.3"

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (2)

Affects 2 ecosystems: nuget (1), pypi (1).

PackageEcosystemAffectedFixed In
Microsoft.SemanticKernel.Core
nuget
0.12.207.1-preview, 0.13.277.1-preview, 0.13.442.1-preview, 0.14.547.1-preview (+109 more)1.71.0
semantic-kernel
pypi
0.0.1.dev0, 0.1.0.dev0, 0.2.0.dev0, 0.2.1.dev0 (+121 more)1.39.3

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 9.9 score means for each attack dimension.

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Frequently Asked Questions

What is CVE-2026-25592?
Semantic Kernel has Arbitrary File Write via AI Agent Function Calling in .NET SDK This vulnerability has been assigned a severity rating of CRITICAL (CVSS score: 9.9/10).
How do I check if my project is affected by CVE-2026-25592?
CVE-2026-25592 affects Microsoft.SemanticKernel.Core and semantic-kernel. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-25592 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score
9.9

Exploitation is straightforward and causes maximum impact. Patch immediately.

Also Known As

GHSA-2ww3-72rp-wpp4
PYSEC-2026-531

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