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Path TraversalWeakness · CWE-22

CVE-2026-25592

CRITICAL · 9.9 CVSS v3.1 Published 2026-02-06
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Semantic Kernel .NET SDK versions prior to 1.71.0 contain an Arbitrary File Write vulnerability in the SessionsPythonPlugin. The flaw affects DownloadFileAsync and UploadFileAsync functions which lack proper path validation, allowing attackers to write files to arbitrary locations on the filesystem.

MitigationUpgrade to Microsoft.SemanticKernel.Core version 1.71.0. Alternatively, implement a Function Invocation Filter that allow-lists the localFilePath parameter for file operations to prevent path traversal.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Semantic Kernel SDK version
    Check your project file (.csproj) for the Microsoft.SemanticKernel package version, or run: dotnet list package Microsoft.SemanticKernel
    Affected if Version is lower than 1.71.0
  2. Locate SessionsPythonPlugin usage in codebase
    Search source code for 'SessionsPythonPlugin' references using grep or IDE search: var plugin = new SessionsPythonPlugin(...) or services.AddSingleton<SessionsPythonPlugin>()
    Affected if SessionsPythonPlugin is instantiated or registered in the application
  3. Identify vulnerable function calls
    Search for DownloadFileAsync and UploadFileAsync method calls in code that uses the SessionsPythonPlugin instance
    Affected if Code calls DownloadFileAsync or UploadFileAsync methods on SessionsPythonPlugin
  4. Inspect file path parameters at runtime
    If plugin is in use, examine the localFilePath parameter passed to these functions - check if it accepts user-supplied input or lacks validation
    Affected if localFilePath parameter accepts unvalidated input or allows path traversal sequences like ../

You are affected if Semantic Kernel SDK version is below 1.71.0 AND your application uses SessionsPythonPlugin with DownloadFileAsync or UploadFileAsync functions where localFilePath lacks validation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Interim mitigation

Upgrade to Microsoft.SemanticKernel.Core version 1.71.0. Alternatively, implement a Function Invocation Filter that allow-lists the localFilePath parameter for file operations to prevent path traversal.

Recommended fix High confidence

Microsoft.SemanticKernel.Core version 1.71.0

  1. 1. Identify the current version of Microsoft.SemanticKernel.Core package in your project (check .csproj or packages.config)
  2. 2. Update the Microsoft.SemanticKernel.Core NuGet package reference to version 1.71.0 or later
  3. 3. Run 'dotnet restore' or 'nuget restore' to fetch the updated package
  4. 4. Rebuild the solution to ensure compatibility
  5. 5. Test the application, particularly any functionality using SessionsPythonPlugin with DownloadFileAsync or UploadFileAsync
  6. 6. As an additional defense-in-depth measure, implement a Function Invocation Filter that allow-lists the localFilePath argument for file operations
Caveat Review SemanticKernel 1.71.0 release notes for any breaking changes between your current version and 1.71.0

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the patch applied

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-25592 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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