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TI-2026-42681 Aliases CVE-2026-59866GHSA-4vv7-jj25-4gh6

Kiota: Arbitrary file write + code-injection via x-ms-kiota-info clientClassName and clientNamespaceName

Priority MEDIUM 51CWE-22Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-94.

Summary

Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.5, Kiota emitted x-ms-kiota-info clientClassName and clientNamespaceName values without identifier or path sanitization as both generated client class or namespace names and generated output path components when `kiota generate` ran without -c/--class-name, allowing an attacker-controlled or compromised OpenAPI description to write generated source outside the -o output directory and inject arbitrary text into generated class or namespace declarations. This issue is fixed in version 1.29.1 and 1.32.5 by GenerationConfiguration.SanitizeClientClassName and SanitizeClientNamespaceName.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01413 72nd percentileScored 2026-11-07
Fix Fixed kiota (microsoft): 1.31.1, 1.29.1Microsoft.OpenApi.Kiota (NuGet): 1.32.5, 1.29.1+1 more product

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Microsoftkiota1.30.0 to before 1.31.1; before 1.29.11.31.1, 1.29.1Patch availableCNA
—Microsoft.OpenApi.Kiota (NuGet)1.30.0 to before 1.32.51.32.5Patch availableGHSA-4vv7-jj25-4gh6
—Microsoft.OpenApi.Kiota.Builder (NuGet)1.30.0 to before 1.32.51.32.5Patch availableGHSA-4vv7-jj25-4gh6
—Microsoft.OpenApi.Kiota (NuGet)before 1.29.11.29.1Patch availableGHSA-4vv7-jj25-4gh6
—Microsoft.OpenApi.Kiota.Builder (NuGet)before 1.29.11.29.1Patch availableGHSA-4vv7-jj25-4gh6
  • kiota VendorMicrosoft Affected 1.30.0 to before 1.31.1; before 1.29.1 Fixed in 1.31.1, 1.29.1 Patch available CNA
  • Microsoft.OpenApi.Kiota (NuGet) Vendor— Affected 1.30.0 to before 1.32.5 Fixed in 1.32.5 Patch available GHSA-4vv7-jj25-4gh6
  • Microsoft.OpenApi.Kiota.Builder (NuGet) Vendor— Affected 1.30.0 to before 1.32.5 Fixed in 1.32.5 Patch available GHSA-4vv7-jj25-4gh6
  • Microsoft.OpenApi.Kiota (NuGet) Vendor— Affected before 1.29.1 Fixed in 1.29.1 Patch available GHSA-4vv7-jj25-4gh6
  • Microsoft.OpenApi.Kiota.Builder (NuGet) Vendor— Affected before 1.29.1 Fixed in 1.29.1 Patch available GHSA-4vv7-jj25-4gh6

Remediation

  • Fix · CNA kiota (microsoft) Fixed in 1.31.1, 1.29.1
  • Fix · GHSA-4vv7-jj25-4gh6 Microsoft.OpenApi.Kiota (NuGet) Fixed in 1.32.5 Advisory →
  • Fix · GHSA-4vv7-jj25-4gh6 Microsoft.OpenApi.Kiota.Builder (NuGet) Fixed in 1.32.5 Advisory →
  • Fix · GHSA-4vv7-jj25-4gh6 Microsoft.OpenApi.Kiota (NuGet) Fixed in 1.29.1 Advisory →
  • Fix · GHSA-4vv7-jj25-4gh6 Microsoft.OpenApi.Kiota.Builder (NuGet) Fixed in 1.29.1 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-59866
  2. 2026-10-03 Alias added: GHSA-4vv7-jj25-4gh6

References

Advisory 1

Other 5

  • TI-2026-42212 Microsoft SharePoint Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-37256 Microsoft SharePoint Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-26194 Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-16982 Microsoft SharePoint Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2025-36863 Windows Server Update Service (WSUS) Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2025-33671 Microsoft SharePoint Server Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
See all 18045 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences