{"id":"CVE-2026-25592","aliases":["EUVD-2026-5582","GHSA-2ww3-72rp-wpp4","PYSEC-2026-531"],"status":"published","title":"Semantic Kernel has an Arbitrary File Write via AI Agent Function Calling in .NET SDK","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.","severity":{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.02521,"percentile":0.84985,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-22"],"published":"2026-02-06T18:37:24Z","modified":"2026-10-28T02:31:10Z","fixes":[{"ecosystem":"PyPI","package":"semantic-kernel","fixed_in":["1.39.3"],"sources":["ghsa","osv"]},{"ecosystem":"NuGet","package":"Microsoft.SemanticKernel.Core","fixed_in":["1.71.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"semantic-kernel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.39.3"}]}]},{"source":"ghsa","ecosystem":"NuGet","package":"Microsoft.SemanticKernel.Core","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.71.0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"semantic-kernel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.39.3"}]}],"versions":["0.0.1.dev0","0.1.0.dev0","0.2.0.dev0","0.2.1.dev0","0.2.2.dev0","0.2.3.dev0","0.2.4.dev0","0.2.5.dev0","0.2.6.dev0","0.2.7.dev0","0.2.8.dev0","0.2.9.dev0","0.3.0.dev0","0.3.1.dev0","0.3.10.dev0","0.3.11.dev0","0.3.12.dev0","0.3.13.dev0","0.3.14.dev0","0.3.15.dev0","0.3.2.dev0","0.3.3.dev0","0.3.4.dev0","0.3.5.dev0","0.3.6.dev0","0.3.7.dev0","0.3.8.dev0","0.3.9.dev0","0.4.0.dev0","0.4.1.dev0","0.4.2.dev0","0.4.3.dev0","0.4.4.dev0","0.4.5.dev0","0.4.6.dev0","0.4.7.dev0","0.5.0.dev0","0.5.1.dev0","0.9.0b1","0.9.1b1","0.9.2b1","0.9.3b1","0.9.4b1","0.9.5b1","0.9.6b1","0.9.7b1","0.9.8b1","0.9.9b1","1.0.0","1.0.0rc1","1.0.1","1.0.2","1.0.3","1.0.4","1.0.5","1.1.0","1.1.1","1.1.2","1.10.0","1.10.1","1.11.0","1.12.0","1.12.1","1.13.0","1.14.0","1.15.0","1.16.0","1.17.0","1.17.1","1.18.0","1.18.1","1.18.2","1.19.0","1.2.0","1.20.0","1.21.0","1.21.1","1.21.2","1.21.3","1.22.0","1.22.1","1.23.0","1.23.1","1.24.0","1.24.1","1.25.0","1.26.0","1.26.1","1.27.0","1.27.1","1.27.2","1.28.0","1.28.1","1.29.0","1.3.0","1.30.0","1.31.0","1.32.0","1.32.1","1.32.2","1.33.0","1.34.0","1.35.0","1.35.1","1.35.2","1.35.3","1.36.0","1.36.1","1.36.2","1.37.0","1.37.1","1.38.0","1.39.0","1.39.1","1.39.2","1.4.0","1.5.0","1.5.1","1.6.0","1.7.0","1.8.0","1.8.1","1.8.2","1.8.3","1.9.0"]},{"source":"osv","ecosystem":"NuGet","package":"Microsoft.SemanticKernel.Core","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.71.0"}]}],"versions":["0.12.207.1-preview","0.13.277.1-preview","0.13.442.1-preview","0.14.547.1-preview","0.15.230531.5-preview","0.15.230609.2-preview","0.15.231219.1-preview","0.16.230615.1-preview","0.17.230626.1-preview","1.0.0-beta1","1.0.0-beta2","1.0.0-beta3","1.0.0-beta4","1.0.0-beta5","1.0.0-beta6","1.0.0-beta7","1.0.0-beta8","1.0.0-rc1","1.0.0-rc2","1.0.0-rc3","1.0.0-rc4","1.0.1","1.1.0","1.10.0","1.11.0","1.11.1","1.12.0","1.13.0","1.14.0","1.14.1","1.15.0","1.15.1","1.16.0","1.16.1","1.16.2","1.17.0","1.17.1","1.17.2","1.18.0-rc","1.18.1-rc","1.18.2","1.19.0","1.2.0","1.20.0","1.21.0","1.21.1","1.22.0","1.23.0","1.24.0","1.24.1","1.25.0","1.26.0","1.27.0","1.28.0","1.29.0","1.3.0","1.3.1","1.30.0","1.31.0","1.32.0","1.33.0","1.34.0","1.35.0","1.36.0","1.36.1","1.37.0","1.38.0","1.39.0","1.4.0","1.40.0","1.40.1","1.41.0","1.42.0","1.43.0","1.44.0","1.45.0","1.46.0","1.47.0","1.48.0","1.49.0","1.5.0","1.50.0","1.51.0","1.52.0","1.52.1","1.53.0","1.53.1","1.54.0","1.55.0","1.56.0","1.57.0","1.58.0","1.59.0","1.6.0","1.6.1","1.6.2","1.6.3","1.60.0","1.61.0","1.62.0","1.63.0","1.64.0","1.65.0","1.66.0","1.67.0","1.67.1","1.68.0","1.69.0","1.7.0","1.7.1","1.70.0","1.8.0","1.9.0"]},{"source":"osv","ecosystem":"PyPI","package":"semantic-kernel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.39.3"}]}],"versions":["0.0.1.dev0","0.1.0.dev0","0.2.0.dev0","0.2.1.dev0","0.2.2.dev0","0.2.3.dev0","0.2.4.dev0","0.2.5.dev0","0.2.6.dev0","0.2.7.dev0","0.2.8.dev0","0.2.9.dev0","0.3.0.dev0","0.3.1.dev0","0.3.10.dev0","0.3.11.dev0","0.3.12.dev0","0.3.13.dev0","0.3.14.dev0","0.3.15.dev0","0.3.2.dev0","0.3.3.dev0","0.3.4.dev0","0.3.5.dev0","0.3.6.dev0","0.3.7.dev0","0.3.8.dev0","0.3.9.dev0","0.4.0.dev0","0.4.1.dev0","0.4.2.dev0","0.4.3.dev0","0.4.4.dev0","0.4.5.dev0","0.4.6.dev0","0.4.7.dev0","0.5.0.dev0","0.5.1.dev0","0.9.0b1","0.9.1b1","0.9.2b1","0.9.3b1","0.9.4b1","0.9.5b1","0.9.6b1","0.9.7b1","0.9.8b1","0.9.9b1","1.0.0","1.0.0rc1","1.0.1","1.0.2","1.0.3","1.0.4","1.0.5","1.1.0","1.1.1","1.1.2","1.10.0","1.10.1","1.11.0","1.12.0","1.12.1","1.13.0","1.14.0","1.15.0","1.16.0","1.17.0","1.17.1","1.18.0","1.18.1","1.18.2","1.19.0","1.2.0","1.20.0","1.21.0","1.21.1","1.21.2","1.21.3","1.22.0","1.22.1","1.23.0","1.23.1","1.24.0","1.24.1","1.25.0","1.26.0","1.26.1","1.27.0","1.27.1","1.27.2","1.28.0","1.28.1","1.29.0","1.3.0","1.30.0","1.31.0","1.32.0","1.32.1","1.32.2","1.33.0","1.34.0","1.35.0","1.35.1","1.3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Kernel has an Arbitrary File Write via AI Agent Function Calling in .NET SDK","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.","status":"published","published":"2026-02-06T20:38:28.77Z","modified":"2026-02-18T23:32:54.483Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"cna"}],"cwes":["CWE-22"],"updated_at":"2026-11-02T13:41:30.911526Z"}],"euvd":[{"id":"EUVD-2026-5582","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.","status":"published","published":"2026-02-06T20:38:28Z","modified":"2026-02-18T23:32:54Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T19:48:37.43406Z"}],"ghsa":[{"id":"GHSA-2ww3-72rp-wpp4","title":"Semantic Kernel has Arbitrary File Write via AI Agent Function Calling in .NET SDK","description":"### 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)","status":"published","published":"2026-02-06T18:37:24Z","modified":"2026-02-20T19:15:46Z","cvss":[{"version":"3.1","score":9.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-22"],"updated_at":"2026-11-02T14:39:26.881079Z"}],"nvd":[{"id":"CVE-2026-25592","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.","status":"published","published":"2026-02-06T21:16:17.647Z","modified":"2026-06-17T10:24:55.03Z","cvss":[{"version":"3.1","score":9.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"secondary"}],"cwes":["CWE-22"],"updated_at":"2026-11-02T14:12:05.52517Z"}],"osv":[{"id":"CVE-2026-25592","title":"Semantic Kernel has an Arbitrary File Write via AI Agent Function Calling in .NET SDK","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.","status":"published","published":"2026-02-06T20:38:28.77Z","modified":"2026-10-28T02:31:10.725613694Z","cvss":[{"version":"3.1","score":9.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-22"],"updated_at":"2026-11-02T15:44:59.438965Z"},{"id":"GHSA-2ww3-72rp-wpp4","title":"Semantic Kernel has Arbitrary File Write via AI Agent Function Calling in .NET SDK","description":"### 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)","status":"published","published":"2026-02-06T18:37:24Z","modified":"2026-06-29T12:26:18.466664657Z","cvss":[{"version":"3.1","score":9.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-22"],"updated_at":"2026-11-02T15:46:35.050232Z"},{"id":"PYSEC-2026-531","title":"Semantic Kernel has Arbitrary File Write via AI Agent Function Calling in .NET SDK","description":"### 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)","status":"published","published":"2026-06-29T11:50:51.513729Z","modified":"2026-07-01T20:23:04.850413Z","cvss":[{"version":"3.1","score":9.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:52:57.671918Z"}]}}