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CRITICAL severity

GHSA-2ww3-72rp-wpp4 Microsoft.SemanticKernel.…

CRITICALFix: microsoft/semantic-kernel#13478

GHSA-2ww3-72rp-wpp4 is a critical-severity (CVSS 9.9) Path Traversal vulnerability in Microsoft.SemanticKernel.Core. A fix is available for Microsoft.SemanticKernel.Core — see the affected versions and patch details below.

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

Also known asCVE-2026-25592PYSEC-2026-531
Published
Feb 6, 2026
Updated
Jun 29, 2026
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Sep 20, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-2ww3-72rp-wpp4.

EPSS Exploitation Probability

via FIRST.org ↗
2.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs84th percentile — riskier than 84% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-2ww3-72rp-wpp4 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

2 pkgs affected
.NETMicrosoft.SemanticKernel.Core🐍semantic-kernel

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet, PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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. 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 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?

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetMicrosoft.SemanticKernel.Coreall versions1.71.0dotnet add package Microsoft.SemanticKernel.Core --version 1.71.0
🐍PyPIsemantic-kernelall versions1.39.3pip install --upgrade 'semantic-kernel==1.39.3'

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.SemanticKernel.Core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update Microsoft.SemanticKernel.Core to 1.71.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2ww3-72rp-wpp4 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-2ww3-72rp-wpp4 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-2ww3-72rp-wpp4. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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 shoul
O3 Security · Impact-Aware SCA

Is GHSA-2ww3-72rp-wpp4 in your dependencies?

O3 Security finds GHSA-2ww3-72rp-wpp4 across NuGet, PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-2ww3-72rp-wpp4: Critical 9.9 severity | O3 Security