9.3
CRITICAL CVSS 4.0
CVE-2026-59866
Kiota: Arbitrary file write + code-injection via x-ms-kiota-info clientClassName and clientNamespaceName
Description

Kiota is an OpenAPI based HTTP Client code generator. Prior to 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 1.32.5 by GenerationConfiguration.SanitizeClientClassName and SanitizeClientNamespaceName.

INFO

Published Date :

July 16, 2026, 4:19 p.m.

Last Modified :

July 16, 2026, 4:19 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-59866 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Microsoft kiota
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 CRITICAL [email protected]
Solution
Update Kiota to version 1.32.5 or later to fix path traversal and code injection vulnerabilities.
  • Update Kiota to version 1.32.5 or later.
  • Ensure client class and namespace names are sanitized.
References to Advisories, Solutions, and Tools
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-59866 is associated with the following CWEs:

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-59866 vulnerability anywhere in the article.

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.