Kiota: Workspace-config poisoning: out-of-repo file write + generation-time SSRF

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Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.5, Kiota honored a poisoned .kiota/workspace.json workspace configuration without validating per-client or per-plugin outputPath values during kiota client generate and kiota plugin generate, allowing a malicious repository or pull request to use absolute paths, rooted POSIX / paths, UNC \\ or // paths, Windows drive X:\ paths, or .. traversal segments to write generated client files outside the workspace root on a developer or CI host. This issue is fixed in version 1.29.1 and 1.32.5.

Source published

16 Jul 2026 14:42:02 UTC

Source modified

17 Aug 2026 15:02:40 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 7.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N

Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.5, Kiota honored a poisoned .kiota/workspace.json workspace configuration without validating per-client or per-plugin outputPath values during kiota client generate and kiota plugin generate, allowing a malicious repository or pull request to use absolute paths, rooted POSIX / paths, UNC \\ or // paths, Windows drive X:\ paths, or .. traversal segments to write generated client files outside the workspace root on a developer or CI host. This issue is fixed in version 1.29.1 and 1.32.5.

Source published

16 Jul 2026 15:16:35 UTC

Source modified

24 Oct 2026 20:10:00 UTC

Observed here

25 Oct 2026 14:19:22 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 7.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

### 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.

Source published

24 Jul 2026 16:11:24 UTC

Source modified

17 Aug 2026 15:00:08 UTC

Observed here

23 Oct 2026 16:01:25 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N

Publisher rating · HIGH