CVE-2026-41134: Microsoft Kiota code injection in generated clients

CVE-2026-41134 · Severity: high · CVSS 7.8 · Published 2026-04-22

Microsoft Kiota is a tool used by developers to automatically generate software code (API clients) from technical descriptions of web services. A security flaw allows a malicious or compromised API description to inject hidden, unauthorized code into the generated software. If a developer uses an untrusted description, the resulting application could contain malicious logic that compromises data or system security.

Technologies: Microsoft Kiota, Microsoft.OpenApi.Kiota, Microsoft.OpenApi.Kiota.Builder, Microsoft.OpenApi.Kiota (NuGet), Microsoft.OpenApi.Kiota.Builder (NuGet). Vendors: Microsoft, NuGet.

Quick answers

Is CVE-2026-41134 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-41134 being exploited in the wild.
How severe is CVE-2026-41134?
High severity, with a CVSS score of 7.8, published 22 April 2026.
Which products and versions are affected?
Microsoft Kiota < 1.31.1; Microsoft.OpenApi.Kiota < 1.31.1; Microsoft.OpenApi.Kiota.Builder < 1.31.1; Microsoft.OpenApi.Kiota (NuGet) ECOSYSTEM:introduced=1.30.0,fixed=1.31.1; and 1 more.
Is there a fix for CVE-2026-41134?
Yes. Microsoft.OpenApi.Kiota (NuGet): upgrade to 1.31.1 or later; Microsoft.OpenApi.Kiota.Builder (NuGet): upgrade to 1.31.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-41134 attacked?
It is attacked with local access, in a software library.
Am I affected by CVE-2026-41134?
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 1.31.1 or later
    dotnet add package Microsoft.OpenApi.Kiota --version 1.31.1
  • Microsoft.OpenApi.Kiota.Builder (NuGet): upgrade to 1.31.1 or later
    dotnet add package Microsoft.OpenApi.Kiota.Builder --version 1.31.1

Technical details

Kiota versions prior to 1.31.1 contain a code-generation literal injection vulnerability (CWE-94). The root cause is insufficient escaping of values from OpenAPI descriptions (such as default values, property names, or parameter mappings) when they are emitted into generated source code. An attacker who provides a malicious OpenAPI document can escape string literal contexts to inject arbitrary statements into the resulting client library. Exploitation requires a developer to run Kiota against a compromised or untrusted OpenAPI specification. The issue is fixed in version 1.31.1, and users are advised to regenerate existing clients after upgrading.

Affected products

  • Microsoft Kiota < 1.31.1
  • Microsoft Microsoft.OpenApi.Kiota < 1.31.1
  • Microsoft Microsoft.OpenApi.Kiota.Builder < 1.31.1

Identifiers

  • CVE-2026-41134
  • GHSA-2hx3-vp6r-mg3f

Timeline

  • 2026-04-13: disclosed: Initial disclosure in microsoft/kiota repository
  • 2026-04-14: advisory: GitHub Advisory published
  • 2026-04-22: other: Published to NVD

References

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