What’s Vulnerable › Vulnerabilities

CVE-2026-59866: Kiota: Arbitrary file write + code-injection via x-ms-kiota-info clientClassName and clientNamespaceName

• Severity: critical (CVSS 9.3 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-16 · updated 2026-10-24
• Weakness: CWE-22

Description

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.

Affected products

• microsoft kiota: from 1.30.0, < 1.31.1; before 1.29.1

References

• https://github.com/microsoft/kiota/commit/dc812dbbf88ef7edf53a890d36b2f9d1460e947d
• https://github.com/microsoft/kiota/pull/7884
• https://github.com/microsoft/kiota/releases/tag/v1.32.5
• https://github.com/microsoft/kiota/security/advisories/GHSA-4vv7-jj25-4gh6

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