GHSA-xg2h-5xr2-29jw
Suggest an improvement- Source
- https://github.com/advisories/GHSA-xg2h-5xr2-29jw
- Import Source
- https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-xg2h-5xr2-29jw/GHSA-xg2h-5xr2-29jw.json
- JSON Data
- https://api.osv.dev/v1/vulns/GHSA-xg2h-5xr2-29jw
- Aliases
- Published
- 2026-07-24T15:44:32Z
- Modified
- 2026-08-17T15:00:07Z
- Severity
-
- 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
- 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
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}, #$var, and #@var within double-quoted strings at runtime, an attacker who controls an OpenAPI specification file can inject arbitrary Ruby code into generated model classes.
Who is impacted
Developers using Kiota to generate Ruby API clients from external or untrusted OpenAPI specifications Teams with CI/CD pipelines configured to automatically regenerate client code from remote specs Applications that deploy generated Ruby code to production servers
Vulnerability details
Affected component: CodeMethodWriter.cs Root cause: The shared SanitizeForQuotedLiteral() function in Writers/StringExtensions.cs does not escape the # character
Attack vectors
OpenAPI default fields in schema properties Property wire-name hash keys in deserializer/serializer methods Any schema-derived string embedded in Ruby double-quoted literals Severity: Critical when generated code reaches production; High for CI/CD environments with access to production secrets; Medium for public third-party specs; Low for developer-controlled specs.
Patches
https://github.com/microsoft/kiota/pull/7746
Workarounds
If you cannot upgrade immediately:
- Audit and sanitize OpenAPI specifications: Review all OpenAPI specification files for any default values or property names containing the # character. Remove or replace any suspicious strings before code generation.
- Code review of generated files: Implement mandatory code review of all generated Ruby files before merging into any branch. Look for double-quoted strings containing #{, #$, or #@ patterns.
- 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.
- Isolate generated code from production: Do not deploy generated Ruby models to production environments unless the specification source has been verified and reviewed.
- 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).
Remediation
Upgrade Kiota to 1.29.1, 1.32.0, or later. Regenerate/refresh existing generated clients as a precaution:
kiota updateRefreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.
- Database specific
{ "cwe_ids": [ "CWE-94" ], "github_reviewed": true, "github_reviewed_at": "2026-07-24T15:44:32Z", "nvd_published_at": "2026-07-16T15:16:35Z", "severity": "HIGH" }- References
-
- https://github.com/microsoft/kiota/security/advisories/GHSA-xg2h-5xr2-29jw
- https://nvd.nist.gov/vuln/detail/CVE-2026-59861
- https://github.com/microsoft/kiota/pull/7746
- https://github.com/microsoft/kiota/commit/fee1b648bb4394ba7ba72de9c0ce4f2a0bad0cb6
- https://github.com/microsoft/kiota
- https://github.com/microsoft/kiota/releases/tag/v1.32.0
Affected packages
NuGet
Microsoft.OpenAPI.Kiota
Package
- Name
- Microsoft.OpenAPI.Kiota
- View open source insights on deps.dev
- Purl
- pkg:nuget/Microsoft.OpenAPI.Kiota
Microsoft.OpenAPI.Kiota.Builder
Package
- Name
- Microsoft.OpenAPI.Kiota.Builder
- View open source insights on deps.dev
- Purl
- pkg:nuget/Microsoft.OpenAPI.Kiota.Builder
Microsoft.OpenApi.Kiota
Package
- Name
- Microsoft.OpenApi.Kiota
- View open source insights on deps.dev
- Purl
- pkg:nuget/Microsoft.OpenApi.Kiota
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0 Unknown introduced version / All previous versions are affectedFixed1.29.1
Affected versions
0.*
1.*
Microsoft.OpenApi.Kiota.Builder
Package
- Name
- Microsoft.OpenApi.Kiota.Builder
- View open source insights on deps.dev
- Purl
- pkg:nuget/Microsoft.OpenApi.Kiota.Builder
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0 Unknown introduced version / All previous versions are affectedFixed1.29.1