---
id: CVE-2026-59863
aliases:
  - GHSA-4rj6-vrwv-wr8m
title: >-
  Microsoft Kiota Workspace-config poisoning: out-of-repo file write +
  generation-time SSRF
summary: >-
  Microsoft Kiota Workspace-config poisoning: out-of-repo file write +
  generation-time SSRF
severity: high
cwe:
  - CWE-22
  - CWE-829
  - CWE-918
vendor: Microsoft
product: Microsoft.OpenApi.Kiota
ecosystem: nuget
affected:
  - Microsoft.OpenApi.Kiota < 1.32.5
  - Microsoft.OpenApi.Kiota.Builder < 1.32.5
patched:
  - Microsoft.OpenApi.Kiota 1.32.5
  - Microsoft.OpenApi.Kiota.Builder 1.32.5
published: '2026-07-24'
updated: '2026-07-24'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-4rj6-vrwv-wr8m'
references:
  - url: 'https://github.com/microsoft/kiota/security/advisories/GHSA-4rj6-vrwv-wr8m'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-59863'
  - url: 'https://github.com/microsoft/kiota/pull/7885'
  - url: >-
      https://github.com/microsoft/kiota/commit/4049327872db7846ace35c9003774d3e3878e4e9
  - url: 'https://github.com/microsoft/kiota/releases/tag/v1.32.5'
  - url: 'https://github.com/advisories/GHSA-4rj6-vrwv-wr8m'
tags:
  - ghsa
  - nuget
epss: 0.01374
epssPercentile: 0.7081
ingestedAt: '2026-07-24T16:33:09.683Z'
---

## Overview

### 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 **1.32.5** (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 **1.32.5** or later. Review any committed workspace configs for `outputPath` values that
point outside the workspace.

## Affected packages

- `Microsoft.OpenApi.Kiota < 1.32.5`
- `Microsoft.OpenApi.Kiota.Builder < 1.32.5`

## Remediation

Upgrade to a patched release:

- `Microsoft.OpenApi.Kiota 1.32.5`
- `Microsoft.OpenApi.Kiota.Builder 1.32.5`