{"id":"CVE-2026-25592","aliases":["GHSA-2ww3-72rp-wpp4","PYSEC-2026-531"],"url":"https://o3.security/vulnerability/CVE-2026-25592","summary":"Semantic Kernel has an Arbitrary File Write via AI Agent Function Calling in .NET SDK","details":"### Impact\n_What kind of vulnerability is it? Who is impacted?_\nAn Arbitrary File Write vulnerability has been identified in Microsoft's Semantic Kernel .NET SDK, specifically within the `SessionsPythonPlugin`.\nDevelopers who have built applications which include Microsoft's Semantic Kernel .NET SDK and are using the `SessionsPythonPlugin`\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\nThe 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 should upgrade to version 1.71.0 or higher.\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\nUsers can create a [Function Invocation Filter](https://learn.microsoft.com/en-us/semantic-kernel/concepts/enterprise-readiness/filters?pivots=programming-language-csharp#function-invocation-filter) which checks the arguments being passed to any calls to `DownloadFileAsync ` or `UploadFileAsync` and ensures the provided `localFilePath` is allow listed.\n\n### References\n_Are there any links users can visit to find out more?_\n- [Sample showing safe use of the CodeInterpreterPlugin](https://github.com/microsoft/semantic-kernel/blob/main/dotnet/samples/Demos/CodeInterpreterPlugin/Program.cs#L61-L64)\n- [PR to Add file upload security controls to SessionsPythonPlugin](https://github.com/microsoft/semantic-kernel/pull/13478/changes#diff-88d3cacba2bfa84eef8f2aa171b34f9940338cbb784a3ffc49f5fe3af1b8943d)","published":"2026-02-06T20:38:28.770Z","modified":"2026-10-28T02:31:10.725613694Z","cvss":{"score":9.9,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"NuGet","name":"Microsoft.SemanticKernel.Core","fixedVersion":"1.71.0"},{"ecosystem":"PyPI","name":"semantic-kernel","fixedVersion":"1.39.3"}],"fix":{"url":"https://github.com/microsoft/semantic-kernel/pull/13478/changes#diff-88d3cacba2bfa84eef8f2aa171b34f9940338cbb784a3ffc49f5fe3af1b8943d","label":"microsoft/semantic-kernel#13478"},"references":[{"type":"WEB","url":"https://github.com/microsoft/semantic-kernel/blob/main/dotnet/samples/Demos/CodeInterpreterPlugin/Program.cs#L61-L64"},{"type":"WEB","url":"https://github.com/microsoft/semantic-kernel/pull/13478/changes#diff-88d3cacba2bfa84eef8f2aa171b34f9940338cbb784a3ffc49f5fe3af1b8943d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25592.json"},{"type":"ADVISORY","url":"https://github.com/microsoft/semantic-kernel/security/advisories/GHSA-2ww3-72rp-wpp4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-25592"},{"type":"PACKAGE","url":"https://github.com/microsoft/semantic-kernel"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:31:10.725613694Z"}}