{"id":"GHSA-xg2h-5xr2-29jw","summary":"Microsoft Kiota: Code Generation Literal Injection in Kiota Ruby Generator","details":"Code Generation Literal Injection in Kiota Ruby Generator Leads to Arbitrary Code Execution\n\n# Impact\n\nThe 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}, #$var, and #@var within double-quoted strings at runtime, an attacker who controls an OpenAPI specification file can inject arbitrary Ruby code into generated model classes.\n\n# Who is impacted\n\nDevelopers using Kiota to generate Ruby API clients from external or untrusted OpenAPI specifications\nTeams with CI/CD pipelines configured to automatically regenerate client code from remote specs\nApplications that deploy generated Ruby code to production servers\n\n# Vulnerability details\n\nAffected component: CodeMethodWriter.cs\nRoot cause: The shared SanitizeForQuotedLiteral() function in Writers/StringExtensions.cs does not escape the # character\n\n# Attack vectors\n\nOpenAPI default fields in schema properties\nProperty wire-name hash keys in deserializer/serializer methods\nAny schema-derived string embedded in Ruby double-quoted literals\nSeverity: Critical when generated code reaches production; High for CI/CD environments with access to production secrets; Medium for public third-party specs; Low for developer-controlled specs.\n\n# Patches\n\nhttps://github.com/microsoft/kiota/pull/7746\n\n# Workarounds\n\nIf you cannot upgrade immediately:\n\n1. Audit and sanitize OpenAPI specifications: Review all OpenAPI specification files for any default values or property names containing the # character. Remove or replace any suspicious strings before code generation.\n1. Code review of generated files: Implement mandatory code review of all generated Ruby files before merging into any branch. Look for double-quoted strings containing #{, #$, or #@ patterns.\n1. Restrict specification sources: Only consume OpenAPI specifications from trusted internal sources. Avoid automatic code generation from external or third-party APIs until this patch is applied.\n1. Isolate generated code from production: Do not deploy generated Ruby models to production environments unless the specification source has been verified and reviewed.\n1. Manual escaping (temporary): If regeneration is not possible, manually inspect and edit generated files to escape any # characters in string literals (replace # with \\# in double-quoted strings).\n\n# Remediation\n\nUpgrade Kiota to 1.29.1, 1.32.0, or later.\nRegenerate/refresh existing generated clients as a precaution:\n\n```shell\nkiota update\n```\n\nRefreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.","aliases":["CVE-2026-59861"],"modified":"2026-08-17T15:00:07.956100873Z","published":"2026-07-24T15:44:32Z","database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-07-24T15:44:32Z","nvd_published_at":"2026-07-16T15:16:35Z","cwe_ids":["CWE-94"]},"references":[{"type":"WEB","url":"https://github.com/microsoft/kiota/security/advisories/GHSA-xg2h-5xr2-29jw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59861"},{"type":"WEB","url":"https://github.com/microsoft/kiota/pull/7746"},{"type":"WEB","url":"https://github.com/microsoft/kiota/commit/fee1b648bb4394ba7ba72de9c0ce4f2a0bad0cb6"},{"type":"PACKAGE","url":"https://github.com/microsoft/kiota"},{"type":"WEB","url":"https://github.com/microsoft/kiota/releases/tag/v1.32.0"}],"affected":[{"package":{"name":"Microsoft.OpenAPI.Kiota","ecosystem":"NuGet","purl":"pkg:nuget/Microsoft.OpenAPI.Kiota"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.30.0"},{"fixed":"1.32.0"}]}],"versions":["1.30.0","1.31.0","1.31.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-xg2h-5xr2-29jw/GHSA-xg2h-5xr2-29jw.json"}},{"package":{"name":"Microsoft.OpenAPI.Kiota.Builder","ecosystem":"NuGet","purl":"pkg:nuget/Microsoft.OpenAPI.Kiota.Builder"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.30.0"},{"fixed":"1.32.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-xg2h-5xr2-29jw/GHSA-xg2h-5xr2-29jw.json"}},{"package":{"name":"Microsoft.OpenApi.Kiota","ecosystem":"NuGet","purl":"pkg:nuget/Microsoft.OpenApi.Kiota"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.29.1"}]}],"versions":["0.1.0-preview","0.1.1-preview","0.1.2-preview","0.1.3-preview","0.10.0-preview","0.11.0-preview","0.11.1-preview","0.2.0-preview","0.2.1-preview","0.3.0-preview","0.4.0-preview","0.5.0-preview","0.5.1-preview","0.6.0-preview","0.7.1-preview","0.8.3-preview","0.9.0-preview","1.0.0","1.0.1","1.1.0","1.1.1","1.1.2","1.1.3","1.10.0","1.10.1","1.11.0","1.11.1","1.12.0","1.13.0","1.14.0","1.15.0","1.16.0","1.17.0","1.18.0","1.19.0","1.19.1","1.2.0","1.2.1","1.20.0","1.21.0","1.22.0","1.22.1","1.22.2","1.22.3","1.23.0","1.24.0","1.24.1","1.24.2","1.24.3","1.25.1","1.26.0","1.26.1","1.27.0","1.28.0","1.29.0","1.3.0","1.4.0","1.5.0","1.5.1","1.6.1","1.7.0","1.8.0","1.8.1","1.8.2","1.9.0","1.9.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-xg2h-5xr2-29jw/GHSA-xg2h-5xr2-29jw.json"}},{"package":{"name":"Microsoft.OpenApi.Kiota.Builder","ecosystem":"NuGet","purl":"pkg:nuget/Microsoft.OpenApi.Kiota.Builder"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.29.1"}]}],"versions":["0.2.0-preview","0.3.0-preview","0.4.0-preview","0.5.0-preview","0.5.1-preview","0.6.0-preview","0.7.1-preview","1.0.0","1.0.1","1.1.0","1.1.1","1.1.2","1.1.3","1.10.0","1.10.1","1.11.0","1.11.1","1.12.0","1.13.0","1.14.0","1.15.0","1.16.0","1.17.0","1.18.0","1.19.0","1.19.1","1.2.0","1.2.1","1.20.0","1.21.0","1.22.0","1.22.1","1.22.2","1.22.3","1.23.0","1.3.0","1.4.0","1.5.0","1.5.1","1.6.1","1.7.0","1.8.0","1.8.1","1.8.2","1.9.0","1.9.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-xg2h-5xr2-29jw/GHSA-xg2h-5xr2-29jw.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}