CVE-2026-25592
Critical
Description
Semantic Kernel is an SDK used to build, orchestrate, and deploy AI agents and multi-agent systems. Prior to 1.71.0, an Arbitrary File Write vulnerability has been identified in Microsoft's Semantic Kernel .NET SDK, specifically within the SessionsPythonPlugin. The problem has been fixed in Microsoft.SemanticKernel.Core version 1.71.0. As a mitigation, 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.
SeverityCritical
CVSS9.9
Exploit probability—
ProductMicrosoft.semantickernel.core
PublishedFeb 6, 2026
First seenFeb 6, 2026
Weakness typeCWE-22Path traversal
How to fix
Update
- Microsoft.SemanticKernel.Core1.71.0 or later
- semantic-kernel1.39.3 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Microsoft.SemanticKernel.CoreNuGet | v < 1.71.0 | 1.71.0 |
| semantic-kernelPyPI | v < 1.39.3 | 1.39.3 |
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