{"id":"CVE-2026-41134","aliases":["EUVD-2026-25094","GHSA-2hx3-vp6r-mg3f"],"status":"published","title":"Kiota: Code Generation Literal Injection","description":"Kiota is an OpenAPI based HTTP Client code generator. Versions prior to 1.29.1 and 1.31.1 are affected by a code-generation literal injection vulnerability in multiple writer sinks (for example: serialization/deserialization keys, path/query parameter mappings, URL template metadata, enum/property metadata, and default value emission). When malicious values from an OpenAPI description are emitted into generated source without context-appropriate escaping, an attacker can break out of string literals and inject additional code into generated clients. This issue is only practically exploitable when the OpenAPI description used for generation is from an untrusted source, or a normally trusted OpenAPI description has been compromised/tampered with. Only generating from trusted, integrity-protected API descriptions significantly reduces the risk. To remediate the issue, upgrade Kiota to 1.29.1, 1.31.1, or later and regenerate/refresh existing generated clients as a precaution. Refreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.","severity":{"version":"4.0","score":7.3,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00421,"percentile":0.36775,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-94"],"published":"2026-04-14T23:39:41Z","modified":"2026-11-07T02:30:35Z","fixes":[{"ecosystem":"NuGet","package":"Microsoft.OpenApi.Kiota","fixed_in":["1.31.1","1.29.1"],"sources":["ghsa","osv"]},{"ecosystem":"NuGet","package":"Microsoft.OpenApi.Kiota.Builder","fixed_in":["1.31.1","1.29.1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"NuGet","package":"Microsoft.OpenApi.Kiota","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.30.0"},{"fixed":"1.31.1"}]}]},{"source":"ghsa","ecosystem":"NuGet","package":"Microsoft.OpenApi.Kiota.Builder","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.30.0"},{"fixed":"1.31.1"}]}]},{"source":"ghsa","ecosystem":"NuGet","package":"Microsoft.OpenApi.Kiota","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.29.1"}]}]},{"source":"ghsa","ecosystem":"NuGet","package":"Microsoft.OpenApi.Kiota.Builder","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.29.1"}]}]},{"source":"osv","ecosystem":"NuGet","package":"Microsoft.OpenApi.Kiota","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.30.0"},{"fixed":"1.31.1"}]}],"versions":["1.30.0","1.31.0"]},{"source":"osv","ecosystem":"NuGet","package":"Microsoft.OpenApi.Kiota.Builder","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.30.0"},{"fixed":"1.31.1"}]}]},{"source":"osv","ecosystem":"NuGet","package":"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"]},{"source":"osv","ecosystem":"NuGet","package":"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"]}],"products":[{"vendor":"microsoft","product":"kiota"}],"references":[{"url":"https://github.com/microsoft/kiota/security/advisories/GHSA-2hx3-vp6r-mg3f","tags":["x_refsource_CONFIRM","Exploit","Vendor Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41134","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-2hx3-vp6r-mg3f"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41134.json","tags":["advisory"]},{"url":"https://github.com/microsoft/kiota","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-41134","title":"Kiota: Code Generation Literal Injection","description":"Kiota is an OpenAPI based HTTP Client code generator. Versions prior to 1.29.1 and 1.31.1 are affected by a code-generation literal injection vulnerability in multiple writer sinks (for example: serialization/deserialization keys, path/query parameter mappings, URL template metadata, enum/property metadata, and default value emission). When malicious values from an OpenAPI description are emitted into generated source without context-appropriate escaping, an attacker can break out of string literals and inject additional code into generated clients. This issue is only practically exploitable when the OpenAPI description used for generation is from an untrusted source, or a normally trusted OpenAPI description has been compromised/tampered with. Only generating from trusted, integrity-protected API descriptions significantly reduces the risk. To remediate the issue, upgrade Kiota to 1.29.1, 1.31.1, or later and regenerate/refresh existing generated clients as a precaution. Refreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.","status":"published","published":"2026-04-22T20:20:57.541Z","modified":"2026-08-17T15:01:15.166Z","cvss":[{"version":"4.0","score":7.3,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-94"],"updated_at":"2026-11-02T13:40:57.334596Z"}],"euvd":[{"id":"EUVD-2026-25094","description":"Kiota is an OpenAPI based HTTP Client code generator. Versions prior to 1.29.1 and 1.31.1 are affected by a code-generation literal injection vulnerability in multiple writer sinks (for example: serialization/deserialization keys, path/query parameter mappings, URL template metadata, enum/property metadata, and default value emission). When malicious values from an OpenAPI description are emitted into generated source without context-appropriate escaping, an attacker can break out of string literals and inject additional code into generated clients. This issue is only practically exploitable when the OpenAPI description used for generation is from an untrusted source, or a normally trusted OpenAPI description has been compromised/tampered with. Only generating from trusted, integrity-protected API descriptions significantly reduces the risk. To remediate the issue, upgrade Kiota to 1.29.1, 1.31.1, or later and regenerate/refresh existing generated clients as a precaution. Refreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.","status":"published","published":"2026-04-22T20:20:57Z","modified":"2026-08-17T15:01:15Z","cvss":[{"version":"4.0","score":7.3,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T18:01:49.335011Z"}],"ghsa":[{"id":"GHSA-2hx3-vp6r-mg3f","title":"Kiota: Code Generation Literal Injection","description":"# CVE Advisory (CVE-2026-41134): Code Generation Literal Injection in Kiota\n\n## Summary\n\nKiota versions **prior to 1.29.1 and 1.31.1** are affected by a code-generation literal injection vulnerability in multiple writer sinks (for example: serialization/deserialization keys, path/query parameter mappings, URL template metadata, enum/property metadata, and default value emission).\n\nWhen malicious values from an OpenAPI description are emitted into generated source without context-appropriate escaping, an attacker can break out of string literals and inject additional code into generated clients.\n\n## Impact and Preconditions\n\nThis issue is only practically exploitable when:\n\n1. the OpenAPI description used for generation is from an **untrusted source**, or\n2. a normally trusted OpenAPI description has been **compromised/tampered with**.\n\nIf you only generate from trusted, integrity-protected API descriptions, risk is significantly reduced.\n\n## Affected Versions\n\n- **Affected:** all versions **\u003c 1.29.1** and **\u003e= 1.30.0, \u003c 1.31.1**\n- **Fixed:** **1.29.1, 1.31.1,** and later\n\n## Illustrative Exploit Example\n\n### Example OpenAPI fragment (malicious default value)\n\n```yaml\nopenapi: 3.0.1\ninfo:\n  title: Exploit Demo\n  version: 1.0.0\ncomponents:\n  schemas:\n    User:\n      type: object\n      properties:\n        displayName:\n          type: string\n          default: \"\\\"; throw new System.Exception(\\\"injected\\\"); //\"\n```\n\n### Example generated C# snippet before fix (illustrative)\n\n```csharp\npublic User() {\n    DisplayName = \"\"; throw new System.Exception(\"injected\"); //\";\n}\n```\n\nThe injected payload escapes the intended string context and introduces attacker-controlled statements in generated code.\n\n\u003e Note: this exploit is not limited to default values, but may also impact properties names (serialization), path or query parameters, enum representations and other locations.\n\n## Remediation\n\n1. Upgrade Kiota to **1.31.1 or later**.\n2. Regenerate/refresh existing generated clients as a precaution:\n\n```bash\nkiota update\n```\n\nRefreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.\n\n## Acknowledgement\n\nWe would like to thank the researcher Thanatos Tian（Polyu) for finding this issue and for his contribution to this open source project.","status":"published","published":"2026-04-14T23:39:41Z","modified":"2026-08-17T14:58:39Z","cvss":[{"version":"4.0","score":7.3,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"},{"version":"3.1","score":0,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N","level":"none"}],"cwes":["CWE-94"],"updated_at":"2026-11-02T14:41:01.23108Z"}],"nvd":[{"id":"CVE-2026-41134","description":"Kiota is an OpenAPI based HTTP Client code generator. Versions prior to 1.29.1 and 1.31.1 are affected by a code-generation literal injection vulnerability in multiple writer sinks (for example: serialization/deserialization keys, path/query parameter mappings, URL template metadata, enum/property metadata, and default value emission). When malicious values from an OpenAPI description are emitted into generated source without context-appropriate escaping, an attacker can break out of string literals and inject additional code into generated clients. This issue is only practically exploitable when the OpenAPI description used for generation is from an untrusted source, or a normally trusted OpenAPI description has been compromised/tampered with. Only generating from trusted, integrity-protected API descriptions significantly reduces the risk. To remediate the issue, upgrade Kiota to 1.29.1, 1.31.1, or later and regenerate/refresh existing generated clients as a precaution. Refreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.","status":"published","published":"2026-04-22T21:17:09.027Z","modified":"2026-10-26T22:10:00.163Z","cvss":[{"version":"4.0","score":7.3,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-94"],"updated_at":"2026-11-02T14:12:15.867234Z"}],"osv":[{"id":"CVE-2026-41134","title":"Kiota: Code Generation Literal Injection","description":"Kiota is an OpenAPI based HTTP Client code generator. Versions prior to 1.29.1 and 1.31.1 are affected by a code-generation literal injection vulnerability in multiple writer sinks (for example: serialization/deserialization keys, path/query parameter mappings, URL template metadata, enum/property metadata, and default value emission). When malicious values from an OpenAPI description are emitted into generated source without context-appropriate escaping, an attacker can break out of string literals and inject additional code into generated clients. This issue is only practically exploitable when the OpenAPI description used for generation is from an untrusted source, or a normally trusted OpenAPI description has been compromised/tampered with. Only generating from trusted, integrity-protected API descriptions significantly reduces the risk. To remediate the issue, upgrade Kiota to 1.29.1, 1.31.1, or later and regenerate/refresh existing generated clients as a precaution. Refreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.","status":"published","published":"2026-04-22T20:20:57.541Z","modified":"2026-11-07T02:30:35.005835966Z","cvss":[{"version":"4.0","score":7.3,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-94"],"updated_at":"2026-11-07T03:08:04.910544Z"},{"id":"GHSA-2hx3-vp6r-mg3f","title":"Kiota: Code Generation Literal Injection","description":"# CVE Advisory (CVE-2026-41134): Code Generation Literal Injection in Kiota\n\n## Summary\n\nKiota versions **prior to 1.29.1 and 1.31.1** are affected by a code-generation literal injection vulnerability in multiple writer sinks (for example: serialization/deserialization keys, path/query parameter mappings, URL template metadata, enum/property metadata, and default value emission).\n\nWhen malicious values from an OpenAPI description are emitted into generated source without context-appropriate escaping, an attacker can break out of string literals and inject additional code into generated clients.\n\n## Impact and Preconditions\n\nThis issue is only practically exploitable when:\n\n1. the OpenAPI description used for generation is from an **untrusted source**, or\n2. a normally trusted OpenAPI description has been **compromised/tampered with**.\n\nIf you only generate from trusted, integrity-protected API descriptions, risk is significantly reduced.\n\n## Affected Versions\n\n- **Affected:** all versions **\u003c 1.29.1** and **\u003e= 1.30.0, \u003c 1.31.1**\n- **Fixed:** **1.29.1, 1.31.1,** and later\n\n## Illustrative Exploit Example\n\n### Example OpenAPI fragment (malicious default value)\n\n```yaml\nopenapi: 3.0.1\ninfo:\n  title: Exploit Demo\n  version: 1.0.0\ncomponents:\n  schemas:\n    User:\n      type: object\n      properties:\n        displayName:\n          type: string\n          default: \"\\\"; throw new System.Exception(\\\"injected\\\"); //\"\n```\n\n### Example generated C# snippet before fix (illustrative)\n\n```csharp\npublic User() {\n    DisplayName = \"\"; throw new System.Exception(\"injected\"); //\";\n}\n```\n\nThe injected payload escapes the intended string context and introduces attacker-controlled statements in generated code.\n\n\u003e Note: this exploit is not limited to default values, but may also impact properties names (serialization), path or query parameters, enum representations and other locations.\n\n## Remediation\n\n1. Upgrade Kiota to **1.31.1 or later**.\n2. Regenerate/refresh existing generated clients as a precaution:\n\n```bash\nkiota update\n```\n\nRefreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.\n\n## Acknowledgement\n\nWe would like to thank the researcher Thanatos Tian（Polyu) for finding this issue and for his contribution to this open source project.","status":"published","published":"2026-04-14T23:39:41Z","modified":"2026-08-17T15:15:07.528047266Z","cvss":[{"version":"3.1","score":0,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N","level":"none"},{"version":"4.0","score":7.3,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-94"],"updated_at":"2026-11-02T15:46:34.338541Z"}]}}