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


- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 6 Feb 2026
- **Updated:** 18 Feb 2026
- **Also known as:** GHSA-2ww3-72rp-wpp4, PYSEC-2026-531

## What is CVE-2026-25592?

CVE-2026-25592 is a critical vulnerability in microsoft semantic-kernel, published on 6 Feb 2026. 

### Official 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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-25592?

5 open source packages ship an affected version, including semantic-kernel and Microsoft.SemanticKernel.Core.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `semantic-kernel` | PyPI | All versions | 1.39.3 |
| `semantic-kernel` | PyPI | All versions | 1.39.3 |
| `semantic-kernel` | PyPI | All versions | 1.39.3 |
| `Microsoft.SemanticKernel.Core` | NuGet | All versions | 1.71.0 |
| `Microsoft.SemanticKernel.Core` | NuGet | All versions | 1.71.0 |

## How do I fix CVE-2026-25592?

Upgrade semantic-kernel to 1.39.3 or later.

## Is CVE-2026-25592 being exploited?

There is no known exploitation of CVE-2026-25592 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25592 and fix it if it is affected.

What it is: CVE-2026-25592 is a critical vulnerability in microsoft semantic-kernel, published on 6 Feb 2026. 
Exploitation: There is no known exploitation of CVE-2026-25592 in the wild and no public exploit code.

Affected packages and fixed versions:
- semantic-kernel (PyPI): affected all versions; fixed in 1.39.3
- semantic-kernel (PyPI): affected all versions; fixed in 1.39.3
- semantic-kernel (PyPI): affected all versions; fixed in 1.39.3
- Microsoft.SemanticKernel.Core (NuGet): affected all versions; fixed in 1.71.0
- Microsoft.SemanticKernel.Core (NuGet): affected all versions; fixed in 1.71.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-25592/ (Markdown: https://insights.sbomify.com/CVE-2026-25592/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25592
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25592
- OSV: https://osv.dev/vulnerability/CVE-2026-25592

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25592/
Summaries are generated and may contain mistakes; the official description above is the record.