Path Traversal in Microsoft Semantic-Kernel

CVE-2026-25592

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.

Vulnerability class: Path Traversal (Directory Traversal)

EPSS: 0.024 (82.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-25592?
CVE-2026-25592 is a critical-severity vulnerability in Microsoft Semantic-Kernel, classified under Path Traversal. CVSS score: 9.9/10. Published 2026-02-06.
How severe is CVE-2026-25592?
Critical severity. CVSS v3 base score is 9.9 out of 10.