GHSA-4rj6-vrwv-wr8m Microsoft Kiota Workspace-config poisoning: out-of-repo file write + generation-time SSRF

• NuGet Microsoft.OpenApi.Kiota: >= 1.30.0, < 1.32.5 → fixed in 1.32.5 • NuGet Microsoft.OpenApi.Kiota.Builder: >= 1.30.0, < 1.32.5 → fixed in 1.32.5 • NuGet Microsoft.OpenApi.Kiota: < 1.29.1 → fixed in 1.29.1 • NuGet Microsoft.OpenApi.Kiota.Builder: < 1.29.1 → fixed in 1.29.1

Summary Microsoft Kiota honors a poisoned `.kiota/workspace.json` — the workspace configuration that Kiota's documented team workflow has developers commit to their repository — unvalidated on `kiota client generate` / `kiota plugin generate`. A repository (or pull request) containing a malicious per-client / per-plugin `outputPath` causes Kiota, when a developer or CI runs the documented regenerate command, to (CWE-22) write the entire generated client to an arbitrary path outside the workspace — the `outputPath` was not confined to the workspace root and absolute paths were accepted. Confirmed on Kiota 1.32.4 (`KIOTA_CONFIG_PREVIEW=true`, the self-contained `linux-x64` release binary). Details ```jsonc // .kiota/workspace.json (committed to the repo) "clients": { "MyClient": { "outputPath": "/abs/path/outside/repo/pwned_client" // -> generated client written here (CWE-22) }} ``` Running `kiota client generate --client-name MyClient` in the repo writes `MyClient.cs`, `P/PRequestBuilder.cs`, … to the attacker-chosen `outputPath` (verified outside the working tree). Note on `descriptionLocation` The per-consumer `descriptionLocation` is intentionally fetched at generation time — this is how Kiota knows where to pull an updated description from when refreshing a client, the same way any other value in a committed lock/config file is honored. It is not treated as a vulnerability and is unchanged; only `outputPath` is now confined. Impact A malicious or compromised repository — or a malicious PR that edits `.kiota/workspace.json` — leads to arbitrary file write on the developer's or CI host's filesystem (overwrite source/build files, drop files in auto-loaded locations) whenever a teammate clones/pulls and runs the documented `kiota client generate` / `kiota plugin generate` to refresh the client. CWE-22. This is a different trust boundary from the OpenAPI-description-based findings: the malicious input is the Kiota config, not the spec. Patches Fixed in 1.29.1 and 1.32.5 (https://github.com/microsoft/kiota/pull/7885). On loading a workspace configuration, each client/plugin `outputPath` is validated to be a relative subdirectory of the workspace: null/empty, rooted paths (POSIX `/`, UNC `\\` / `//`, Windows drive `X:\`), and any `..` traversal segment are rejected, and the resolved full path must stay under the workspace root. Generation aborts with an error if any consumer's `outputPath` escapes the workspace. Remediation Upgrade to Kiota 1.29.1, 1.32.5 or later. Review any committed workspace configs for `outputPath` values that point outside the workspace.