{"id":"CVE-2026-59864","aliases":["GHSA-4jwf-m4wg-8p66"],"url":"https://o3.security/vulnerability/CVE-2026-59864","summary":"Kiota: Path/URL injection into generated Copilot plugin manifest via x-ai-* extensions","details":"### Summary\n\n`kiota plugin add` / `kiota plugin generate` (with `-t APIPlugin`) emits an attacker-controlled `static_template.file` path from the AI-plugin extensions (`x-ai-adaptive-card`, `x-ai-capabilities`) **verbatim**, with no path validation, into the generated Microsoft 365 Copilot / Teams plugin manifest (`<name>-apiplugin.json`). An attacker-controlled or compromised OpenAPI description can therefore embed a `../` / absolute path into the manifest's `response_semantics.static_template.file`, yielding a **path traversal (CWE-22)** / out-of-package file inclusion (CWE-829) that is resolved by the AI host when the generated plugin is deployed.\n\nConfirmed on Kiota **1.32.4** (`KIOTA_CONFIG_PREVIEW=true`, the self-contained `linux-x64` release binary).\n\n### Details\n\nBoth extension paths write the `static_template.file` reference straight into the manifest without sanitization — `PluginsGenerationService.GetResponseSemanticsFromAdaptiveCardExtension` mints `static_template = {\"file\": <File>}`, and the `x-ai-capabilities` path copies the `static_template` object through:\n\n```\n# spec                                                  -> generated manifest (functions[].capabilities.response_semantics)\nx-ai-adaptive-card: {title: T, data_path: $.x,\n   file: \"../../../../../../etc/passwd\"}                -> static_template.file = \"../../../../../../etc/passwd\"   (CWE-22)\nx-ai-capabilities.response_semantics.static_template:\n   {file: \"../../../../../../etc/passwd\"}               -> static_template.file = \"../../../../../../etc/passwd\"   (CWE-22)\n```\n\n(`x-ai-adaptive-card.file` only reaches the manifest when `title` is set, so `GetResponseSemanticsFromAdaptiveCardExtension` fires; otherwise kiota writes its own template card instead.)\n\n### Impact\n\n**This is not local code execution on the build host.** The injected path is written into the generated plugin manifest and realized **downstream**, when the plugin is packaged and sideloaded / deployed to an AI host (Microsoft 365 Copilot / Teams) that resolves `static_template.file` relative to the plugin package (out-of-package file reference via `../`). Kiota is the propagation point: it fails to reject `../` and absolute paths in this provider-supplied field before writing it into the manifest.\n\n### Patches\n\nFixed in **1.29.1 and 1.32.5** (https://github.com/microsoft/kiota/pull/7892). `static_template.file` from both `x-ai-adaptive-card` and `x-ai-capabilities` is validated as a relative path confined to the plugin output package: absolute URIs, rooted/UNC paths, Windows drive paths, and `..` traversal segments are rejected, and unsafe references are dropped with a warning. Regression tests cover `..`, absolute paths, and URI values.\n\n### Remediation\n\nUpgrade to Kiota **1.29.1, 1.32.5** or later and regenerate affected plugins.","published":"2026-07-16T14:45:36.247Z","modified":"2026-10-07T07:05:29.479089780Z","cvss":null,"epss":{"score":0.01331,"percentile":0.69557,"asOf":"2026-09-15"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"NuGet","name":"Microsoft.OpenApi.Kiota","fixedVersion":"1.32.5"},{"ecosystem":"NuGet","name":"Microsoft.OpenApi.Kiota.Builder","fixedVersion":"1.32.5"},{"ecosystem":"NuGet","name":"Microsoft.OpenApi.Kiota","fixedVersion":"1.29.1"},{"ecosystem":"NuGet","name":"Microsoft.OpenApi.Kiota.Builder","fixedVersion":"1.29.1"}],"fix":{"url":"https://github.com/microsoft/kiota/commit/9a185994a4e549b7bba3cc2beffb9736aa902e79","label":"microsoft/kiota@9a18599"},"references":[{"type":"WEB","url":"https://github.com/microsoft/kiota/releases/tag/v1.32.5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59864.json"},{"type":"ADVISORY","url":"https://github.com/microsoft/kiota/security/advisories/GHSA-4jwf-m4wg-8p66"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59864"},{"type":"FIX","url":"https://github.com/microsoft/kiota/commit/9a185994a4e549b7bba3cc2beffb9736aa902e79"},{"type":"FIX","url":"https://github.com/microsoft/kiota/pull/7892"},{"type":"PACKAGE","url":"https://github.com/microsoft/kiota"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-07T07:05:29.479089780Z"}}