Microsoft Kiota: Code Generation Literal Injection in Kiota Ruby Generator
CVE-2026-59861GHSA-xg2h-5xr2-29jw
What to do
Vendor fix available. Upgrade each affected package to the fixed version on its release line (microsoft.openapi.kiota 1.32.0, 1.29.1; microsoft.openapi.kiota.builder 1.32.0, 1.29.1), redeploy, then verify what is actually installed.
This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.
Affected packages
NuGet microsoft.openapi.kiota
- Affected
- >= 1.30.0, < 1.32.0< 1.29.1
- Fixed in
- 1.29.1, 1.32.0
NuGet microsoft.openapi.kiota.builder
- Affected
- >= 1.30.0, < 1.32.0< 1.29.1
- Fixed in
- 1.29.1, 1.32.0
Sources
- GitHub Advisory Database and maintainer security advisories on GitHub
GitHub-reviewed advisory GHSA-xg2h-5xr2-29jw lists affected ranges: NuGet microsoft.openapi.kiota >=1.30.0 =0 =1.30.0 =0 <1.29.1
VerifiedObserved Structured GitHub Advisory Database record (type=reviewed) from the GitHub REST API.
Severity and exploitation
- Exploitation
- No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
- CVSS
- 7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- CVE-2026-59861: 2.05% estimated exploitation activity in the next 30 days; percentile 81.24 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description
As published by the source; long descriptions are shortened.
Code Generation Literal Injection in Kiota Ruby Generator Leads to Arbitrary Code Execution Impact The Kiota Ruby code generator is vulnerable to a code generation literal injection attack. The generator embeds string values from OpenAPI default fields and property names directly into Ruby double-quoted string literals without properly escaping the
character. Since Ruby evaluates string interpolation expressions like #{expr}, #$var, and #@var within double-quoted strings at runtime, an attacker who controls an OpenAPI specification file can inject arbitrary Ruby code into generated model classes. Who is impacted Developers using Kiota to generate Ruby API clients from external or untrusted OpenAPI specifications Teams with CI/CD pipelines configured to automatically regenerate client code from remote specs Applications that deploy generated Ruby code to production servers Vulnerability details Affected component: CodeMethodWriter.cs Root cause: The shared SanitizeForQuotedLiteral()…
Dates and revisions
- Published by the source
- Last modified by the source
- Source last checked
- Revision 1 · created ·
Published from ghsa record GHSA-xg2h-5xr2-29jw
Agent brief
Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.
# Patch Next advisory brief: CVE-2026-59861 Advisory: Microsoft Kiota: Code Generation Literal Injection in Kiota Ruby Generator IDs: CVE-2026-59861, GHSA-xg2h-5xr2-29jw Record: https://patchnext.com/advisories/cve-2026-59861 (revision 1, source checked 26 Oct 2026, 17:05 UTC) Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected. Severity: High (CVSS 7.5) Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV. Vendor response: Vendor fix available; fixed versions by package: microsoft.openapi.kiota 1.32.0, 1.29.1; microsoft.openapi.kiota.builder 1.32.0, 1.29.1. A vendor fix does not mean a deployment is fixed. ## Affected components - NuGet microsoft.openapi.kiota: affected >= 1.30.0, < 1.32.0; < 1.29.1; fixed in 1.29.1, 1.32.0 - NuGet microsoft.openapi.kiota.builder: affected >= 1.30.0, < 1.32.0; < 1.29.1; fixed in 1.29.1, 1.32.0 ## Suggested inspection (read-only) - NuGet microsoft.openapi.kiota: check the installed version with your package manager. - NuGet microsoft.openapi.kiota.builder: check the installed version with your package manager. ## Supported action Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version. ## Required regression checks - Run the test suite and a production build. - Exercise the features that depend on microsoft.openapi.kiota, microsoft.openapi.kiota.builder. - Repeat the inspection and confirm that only fixed versions remain installed. ## Rollback considerations - Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward. ## Unresolved questions - Which deployments run an affected version? - Exploitation status can change. Check again before lowering the priority. - Mark the work resolved only after the fixed version is verified in production. ## Sources - Verified: https://github.com/advisories/GHSA-xg2h-5xr2-29jw (GitHub-reviewed advisory GHSA-xg2h-5xr2-29jw lists affected ranges: NuGet microsoft.openapi.kiota >=1.30.0 =0 =1.30.0 =0 <1.29.1) Commands are suggestions: review each one before running it.
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