CVE-2026-59867: Microsoft Kiota SSRF and File Inclusion via OpenAPI external references

CVE-2026-59867 · Severity: high · CVSS 7.1 · Published 2026-07-16

Microsoft Kiota is a tool used by developers to generate software code from API descriptions. A vulnerability in how it handles external references allows an attacker to trick the tool into reading sensitive local files or making unauthorized network requests during the code generation process. This could lead to the exposure of internal company data or cloud credentials if the tool is run on a malicious API specification.

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-2026-59867 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-59867 being exploited in the wild.
How severe is CVE-2026-59867?
High severity, with a CVSS score of 7.1, published 16 July 2026.
Which products and versions are affected?
Microsoft Kiota < 1.32.5; Microsoft.OpenApi.Kiota < 1.32.5; Microsoft.OpenApi.Kiota.Builder < 1.32.5; Microsoft.OpenApi.Kiota (NuGet) ECOSYSTEM:introduced=1.30.0,fixed=1.32.5; and 1 more.
Is there a fix for CVE-2026-59867?
Yes. Microsoft.OpenApi.Kiota (NuGet): upgrade to 1.32.5 or later; Microsoft.OpenApi.Kiota.Builder (NuGet): upgrade to 1.32.5 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-59867 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-59867?
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 1.32.5 or later
    dotnet add package Microsoft.OpenApi.Kiota --version 1.32.5
  • Microsoft.OpenApi.Kiota.Builder (NuGet): upgrade to 1.32.5 or later
    dotnet add package Microsoft.OpenApi.Kiota.Builder --version 1.32.5

Technical details

Microsoft Kiota (prior to version 1.32.5) fails to restrict the resolution of '$ref' pointers within OpenAPI descriptions. An attacker can provide a malicious specification that uses these pointers to trigger Server-Side Request Forgery (SSRF) against internal network resources or Local File Inclusion (LFI) to read arbitrary files from the build host. The contents of these external resources are then inlined into the generated client code. While output escaping prevents direct Remote Code Execution (RCE), the vulnerability allows for significant data exfiltration from developer machines or CI/CD environments. The fix introduces a default-deny policy for external references, requiring explicit opt-in via the '--allowed-external-origins' parameter.

Affected products

  • Microsoft Microsoft.OpenApi.Kiota < 1.32.5
  • Microsoft Microsoft.OpenApi.Kiota.Builder < 1.32.5

Identifiers

  • CVE-2026-59867
  • GHSA-rg4h-fpcp-2qm8

Timeline

  • 2026-07-03: disclosed
  • 2026-07-16: advisory: NVD publication date
  • 2026-07-24: patched: GitHub Advisory published/reviewed

References

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