CVE-2026-59864 — Vulnerability in Microsoft.OpenApi.Kiota — CVE...

### Summary `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. Confirmed on Kiota **1.32.4** (`KIOTA_CONFIG_PREVIEW=true`, the self-contained `linux-x64` release binary). ### Details Both 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: ``` # spec -> generated manifest (functions[].capabilities.response_semantics) x-ai-adaptive-card: {title: T, data_path: $.x, file: "../../../../../../etc/passwd"} -> static_template.file = "../../../../../../etc/passwd" (CWE-22) x-ai-capabilities.response_semantics.static_template: {file: "../../../../../../etc/passwd"} -> static_template.file = "../../../../../../etc/passwd" (CWE-22) ``` (`x-ai-adaptive-card.file` only reaches the manifest when `title` is set, so `GetResponseSemanticsFromAdaptiveCardExtension` fires; otherwise kiota writes its own template card instead.) ### Impact **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. ### Patches Fixed 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. ### Remediation Upgrade to Kiota **1.29.1, 1.32.5** or later and regenerate affected plugins.