---
title: "CVE-2026-25592: Semantic Kernel has Arbitrary File Write via AI Agent Function Calling in .NET SDK"
url: https://erroneo.us/security/cve/CVE-2026-25592/
description: "CVE-2026-25592 (semantic-kernel (PyPI)): Semantic Kernel is an SDK used to build, orchestrate, and deploy AI agents and multi-agent systems. Prior to…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-02-06
date_modified: 2026-02-20
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-25592"
kev: false
cvss: 10
epss: 0.02362
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-25592: Semantic Kernel has Arbitrary File Write via AI Agent Function Calling in .NET SDK

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 2.4% , percentile 84: FIRST’s model estimates a 2.4% chance of exploitation activity in the next 30 days, higher than 84% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes semantic-kernel (PyPI) < 1.39.3, fixed in 1.39.3 ; Microsoft.SemanticKernel.Core (NuGet) < 1.71.0, fixed in 1.71.0 . Check your lockfile, including transitive dependencies.

## What it is

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.

## Affected packages

- PyPI `semantic-kernel` < 1.39.3 → fixed: 1.39.3
- NuGet `Microsoft.SemanticKernel.Core` < 1.71.0 → fixed: 1.71.0

## Affected products (CVE record)

- microsoft semantic-kernel: < 1.71.0

## Severity

- GitHub_M CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.9 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 2.36% probability of exploitation activity in the next 30 days; percentile 84.

## Sources

- [GitHub Advisory GHSA-2ww3-72rp-wpp4](https://github.com/advisories/GHSA-2ww3-72rp-wpp4)
- [CVE.org record CVE-2026-25592](https://www.cve.org/CVERecord?id=CVE-2026-25592)
- [NVD entry CVE-2026-25592](https://nvd.nist.gov/vuln/detail/CVE-2026-25592)
- [github.com](https://github.com/microsoft/semantic-kernel/security/advisories/GHSA-2ww3-72rp-wpp4)
- [github.com](https://github.com/microsoft/semantic-kernel/pull/13478/changes#diff-88d3cacba2bfa84eef8f2aa171b34f9940338cbb784a3ffc49f5fe3af1b8943d)
- [github.com](https://github.com/microsoft/semantic-kernel/blob/main/dotnet/samples/Demos/CodeInterpreterPlugin/Program.cs#L61-L64)

---
Source page: https://erroneo.us/security/cve/CVE-2026-25592/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt