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

Quick assessment

Affected
microsoft kiota
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Microsoft kiota是美国Microsoft公司的API平台生成工具。 Microsoft Kiota 1.32.5之前版本存在安全漏洞，该漏洞源于对x-ms-kiota-info clientClassName和clientNamespaceName值未进行标识符或路径清理，可能允许攻击者控制的或受感染的OpenAPI描述在未指定类名时写入输出目录外的生成源代码并向生成的类或命名空间声明注入任意文本。

CVSS 9.3 · Critical EPSS 1.41% · P72

Possible ATT&CK Techniques 1 AI

T1195.002 · Compromise Software Supply Chain

Affected Version Matrix 2

VendorProduct Version RangeStatus
microsoft kiota >= 1.30.0, < 1.31.1 affected
< 1.29.1 affected
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I. Basic Information for CVE-2026-59866

Vulnerability Information
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Vulnerability Title
Kiota: Arbitrary file write + code-injection via x-ms-kiota-info clientClassName and clientNamespaceName
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
对路径名的限制不恰当(路径遍历)
Source: CVE Program / CVE List V5
Vulnerability Title
Microsoft Kiota 路径遍历漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Microsoft kiota是美国Microsoft公司的API平台生成工具。 Microsoft Kiota 1.32.5之前版本存在安全漏洞，该漏洞源于对x-ms-kiota-info clientClassName和clientNamespaceName值未进行标识符或路径清理，可能允许攻击者控制的或受感染的OpenAPI描述在未指定类名时写入输出目录外的生成源代码并向生成的类或命名空间声明注入任意文本。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
microsoft kiota >= 1.30.0, < 1.31.1 -

II. Public POCs for CVE-2026-59866

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Qwen3.6-35B-A3B · 7288 chars
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III. Intelligence Information for CVE-2026-59866

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Patches & Fixes for CVE-2026-59866 (2)

Vendor Advisories for CVE-2026-59866 (1)

Vendor Pages for CVE-2026-59866 (1)

Same Patch Batch · microsoft · 2026-07-16 · 20 CVEs total

CVE-2026-59864 9.3 CRITICAL Kiota: Path/URL injection into generated Copilot plugin manifest via x-ai-* extensions
CVE-2026-59865 9.3 CRITICAL Kiota: Command injection via x-ms-kiota-info dependencyInstallCommand surfaced by `kiota i
CVE-2026-59860 8.7 HIGH Kiota: XML Doc-Comment Newline Breakout Code Injection
CVE-2026-59859 8.7 HIGH Kiota: Code Generation Literal Injection in the PHP Generator
CVE-2026-57206 8.6 HIGH SimpleChat plugin validation endpoints missing authentication and authorization
CVE-2026-59117 7.5 HIGH Windows Terminal Remote Code Execution Vulnerability
CVE-2026-59861 7.5 HIGH Kiota: Code Generation Literal Injection in Kiota Ruby Generator
CVE-2026-59862 7.5 HIGH Kiota: Code Generation Literal Injection in the Python Generator
CVE-2026-53598 7.5 HIGH Prompty: Arbitrary File Read via ${file:path} Reference Expansion
CVE-2026-59867 7.1 HIGH Kiota: Generation-time SSRF + remote/local file inclusion via unrestricted $ref
CVE-2026-58598 7.0 HIGH Windows Backup Service Elevation of Privilege Vulnerability
CVE-2026-59863 7.0 HIGH Kiota: Workspace-config poisoning: out-of-repo file write + generation-time SSRF
CVE-2026-55440 6.5 MEDIUM Microsoft UFO: COMMAND_RESULTS handler creates unowned sessions, allowing authenticated se
CVE-2026-58643 6.1 MEDIUM Windows Admin Center Spoofing Vulnerability
CVE-2026-62826 4.6 MEDIUM Microsoft SharePoint Server Spoofing Vulnerability
CVE-2026-57205 4.3 MEDIUM SimpleChat: Authenticated users can access other users' profile metadata through user IDOR
CVE-2026-54568 4.3 MEDIUM Microsoft UFO: Missing Authorization in DEVICE_INFO_REQUEST Allows a DEVICE Client to Read
CVE-2026-54733 moodle-local_o365: Authentication bypass via unverified JWT signature in Teams SSO endpoin
CVE-2026-53597 Prompty: Arbitrary code execution via JavaScript frontmatter in TypeScript loader

IV. Related Vulnerabilities

Same product: kiota
Same vendor: microsoft
Same weakness: CWE-22

V. Comments for CVE-2026-59866

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