Arbitrary file write via unsanitized client names
Published Jul 16, 2026 · Updated Jul 16, 2026
Path traversal and code injection in Microsoft Kiota before 1.29.1 and 1.30.0 through 1.32.4 allow attackers to write files. The x-ms-kiota-info clientClassName and clientNamespaceName values flow unsanitized into generated output paths and source declarations. Exploitation requires a developer or CI host to generate a client from an attacker-controlled OpenAPI description without an explicit class name; the result is an out-of-directory file create or overwrite and noncompiling injected text, not code execution.
Summary
What happened
Path traversal and code injection in Microsoft Kiota before 1.29.1 and 1.30.0 through 1.32.4 allow attackers to write files. The x-ms-kiota-info clientClassName and clientNamespaceName values flow unsanitized into generated output paths and source declarations. Exploitation requires a developer or CI host to generate a client from an attacker-controlled OpenAPI description without an explicit class name; the result is an out-of-directory file create or overwrite and noncompiling injected text, not code execution.
The record
- CVE
- CVE-2026-59866
- Published
- Jul 16, 2026
- Updated
- Jul 16, 2026
- Vendor
- Microsoft
- Product
- Kiota
- Classifications
- CWE-94, CWE-22, T1204.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 16, 2026CVE publishedPublication date reported by the CVE source.
- Jul 16, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.32.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GHSA-4vv7-jj25-4gh6 reproduction payloadsproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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