# CVE-2026-59860: Microsoft Kiota code injection in C# XML documentation comments

Source: https://junglewise.ai/threats/cve-2026-59860-microsoft-kiota-code-injection-in-c-xml-documentation-comments  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-16. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-59860 · Severity: high · CVSS 4 · Published 2026-07-16

Microsoft Kiota, a tool used to generate API client code, contains a vulnerability that allows malicious code to be hidden within API descriptions. If a developer uses a compromised or untrusted API specification to generate their code, the tool may inadvertently include and execute harmful commands during the software build process. This could lead to a full system compromise of the developer's environment or the final application.

Technologies: [Microsoft Kiota](https://junglewise.ai/threats/technologies/kiota), [Microsoft.OpenApi.Kiota](https://junglewise.ai/threats/technologies/microsoft-openapi-kiota), [Microsoft.OpenApi.Kiota.Builder](https://junglewise.ai/threats/technologies/microsoft-openapi-kiota-builder), [Microsoft.OpenApi.Kiota (NuGet)](https://junglewise.ai/threats/technologies/nuget-microsoft-openapi-kiota), [Microsoft.OpenApi.Kiota.Builder (NuGet)](https://junglewise.ai/threats/technologies/nuget-microsoft-openapi-kiota-builder). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft), [NuGet](https://junglewise.ai/threats/vendors/nuget).

## Quick answers

**Is CVE-2026-59860 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-59860 being exploited in the wild.

**How severe is CVE-2026-59860?** High severity, with a CVSS score of 4, published 16 July 2026.

**Which products and versions are affected?** Microsoft Kiota < 1.32.3; Microsoft.OpenApi.Kiota < 1.32.3; Microsoft.OpenApi.Kiota.Builder < 1.32.3; Microsoft.OpenApi.Kiota (NuGet) ECOSYSTEM:introduced=1.30.0,fixed=1.32.3; and 1 more.

**Is there a fix for CVE-2026-59860?** Yes. Microsoft.OpenApi.Kiota (NuGet): upgrade to 1.32.3 or later; Microsoft.OpenApi.Kiota.Builder (NuGet): upgrade to 1.32.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-59860 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-59860?** Check whether you run Microsoft Kiota, Microsoft.OpenApi.Kiota, Microsoft.OpenApi.Kiota.Builder or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Microsoft.OpenApi.Kiota (NuGet): upgrade to 1.32.3 or later

  ```sh
  dotnet add package Microsoft.OpenApi.Kiota --version 1.32.3
  ```

- Microsoft.OpenApi.Kiota.Builder (NuGet): upgrade to 1.32.3 or later

  ```sh
  dotnet add package Microsoft.OpenApi.Kiota.Builder --version 1.32.3
  ```


## Technical details

A code injection vulnerability exists in Microsoft Kiota's C# code generation engine due to improper sanitization of input from OpenAPI descriptions. Specifically, the 'description', 'externalDocs' label, and 'externalDocs' link fields are emitted into single-line XML documentation comments (///) without stripping newline (\r, \n) or Unicode line-terminator characters (U+0085, U+2028, U+2029). An attacker can provide a malicious OpenAPI document containing these characters to terminate the comment context and inject arbitrary C# code. This code is then executed when the generated client is compiled by a developer or within a CI/CD pipeline. The vulnerability is fixed in version 1.32.3 by stripping these characters and normalizing tabs.

## Affected products

- Microsoft Microsoft.OpenApi.Kiota < 1.32.3
- Microsoft Microsoft.OpenApi.Kiota.Builder < 1.32.3

## Identifiers

- CVE-2026-59860
- GHSA-3hrf-2gc2-mx32

## Timeline

- 2026-06-25: disclosed: Initial report to Microsoft Kiota repository
- 2026-07-16: advisory: NVD publication date
- 2026-07-24: patched: GitHub Advisory published and fix confirmed in 1.32.3

## References

- [https://api.github.com/users/thegr1ffyn](https://api.github.com/users/thegr1ffyn)
- [https://github.com/thegr1ffyn](https://github.com/thegr1ffyn)
- [https://api.github.com/users/thegr1ffyn/gists%7B/gist_id%7D](https://api.github.com/users/thegr1ffyn/gists%7B/gist_id%7D)
- [https://api.github.com/users/thegr1ffyn/repos](https://api.github.com/users/thegr1ffyn/repos)
- [https://avatars.githubusercontent.com/u/95119705?v=4](https://avatars.githubusercontent.com/u/95119705?v=4)
- [https://api.github.com/users/thegr1ffyn/events%7B/privacy%7D](https://api.github.com/users/thegr1ffyn/events%7B/privacy%7D)

## Related threats

- [Microsoft Kiota documentation-comment injection in Java and PHP](https://junglewise.ai/threats/cve-2026-105796-kiota-is-an-openapi-based-http-client-code-generator-from-0-5-0)
- [Kiota: Unsafe oauth_card_path references in Kiota-generated API plugin manifests](https://junglewise.ai/threats/cve-2026-105795-kiota-is-an-openapi-based-http-client-code-generator-from-1-25-1)
- [Microsoft Kiota path traversal in plugin manifest via percent-encoding bypass](https://junglewise.ai/threats/cve-2026-73851-microsoft-kiota-path-traversal-in-plugin-manifest-via-percent)
- [Microsoft Kiota SSRF and File Inclusion via OpenAPI external references](https://junglewise.ai/threats/cve-2026-59867-microsoft-kiota-ssrf-and-file-inclusion-via-openapi-external)
- [Microsoft Kiota path traversal and code injection in OpenAPI generation](https://junglewise.ai/threats/cve-2026-59866-microsoft-kiota-path-traversal-and-code-injection-in-openapi)