RCE in Microsoft Kiota
CVE-2026-59861
Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.0, Kiota's Ruby generator embedded OpenAPI default fields, property names, and other schema-derived strings through CodeMethodWriter.cs and SanitizeForQuotedLiteral() in Writers/StringExtensions.cs into Ruby double-quoted literals without escaping #, allowing attacker-controlled #{expr}, #$var, or #@var interpolation markers to inject arbitrary Ruby code into generated model classes. This issue is fixed in version 1.29.1 and 1.32.0.
Vulnerability class: RCE (Remote Code Execution)
EPSS: 0.020 (79.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Microsoft Kiota — versions >= 1.30.0, < 1.31.1, < 1.29.1, < 1.32.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-59861?
- CVE-2026-59861 is a high-severity vulnerability in Microsoft Kiota, classified under Code Injection. CVSS score: 7.5/10. Published 2026-07-16.
- How severe is CVE-2026-59861?
- High severity. CVSS v3 base score is 7.5 out of 10.