{"id":"CVE-2026-63346","state":"PUBLISHED","title":"Refitter: C# source injection through OpenAPI header parameter names","description":"Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, the header parameter name in `parameters[].name` with `in: header` is emitted verbatim into a Refit `[Header(\"<name>\")]` attribute string without escaping quotation marks. An attacker-influenced OpenAPI description can pass default validation without `--skip-validation` and break out from the parameter-list position by closing the parameter and method syntax, attribute, interface, and namespace. The generated file can remain valid C# while containing a top-level file class with a `[ModuleInitializer]` method, which executes attacker code when the compiled assembly is loaded at application startup, even if the client is never called. Query `AliasAs` and enum/default value sinks are escaped; this flaw is in header-name attribute-string emission. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2.","publishedAt":"2026-10-30T22:17:02.231Z","updatedAt":"2026-10-30T22:17:02.231Z","severity":{"score":8.6,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["christianhelle refitter"],"affected":[{"vendor":"christianhelle","product":"refitter","versions":[{"version":"< 2.1.2","status":"affected"}]}],"references":["https://github.com/christianhelle/refitter/security/advisories/GHSA-58x9-vjvp-6mx8","https://github.com/christianhelle/refitter/pull/1178","https://github.com/christianhelle/refitter/commit/63a19b03699a9c267d6fab5f758ec26484db83a1","https://github.com/christianhelle/refitter/releases/tag/2.1.2","https://github.com/user-attachments/files/29395048/maintainer-report.txt","https://github.com/user-attachments/files/29395050/make_spec.py","https://github.com/user-attachments/files/29395051/reproduce.sh"],"weaknesses":["CWE-94","CWE-116"],"ingestedAt":"2026-10-30T22:26:06.415Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/63xxx/CVE-2026-63346.json","commit":"f02cde01d713f161fa6518ef321d5dace5470571","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63346","state":"PUBLISHED","datePublished":"2026-10-30T22:17:02.231Z","dateUpdated":"2026-10-30T22:17:02.231Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-16T14:14:24.385Z"},"containers":{"cna":{"title":"Refitter: C# source injection through OpenAPI header parameter names","descriptions":[{"lang":"en","value":"Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, the header parameter name in `parameters[].name` with `in: header` is emitted verbatim into a Refit `[Header(\"<name>\")]` attribute string without escaping quotation marks. An attacker-influenced OpenAPI description can pass default validation without `--skip-validation` and break out from the parameter-list position by closing the parameter and method syntax, attribute, interface, and namespace. The generated file can remain valid C# while containing a top-level file class with a `[ModuleInitializer]` method, which executes attacker code when the compiled assembly is loaded at application startup, even if the client is never called. Query `AliasAs` and enum/default value sinks are escaped; this flaw is in header-name attribute-string emission. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2."}],"affected":[{"vendor":"christianhelle","product":"refitter","versions":[{"version":"< 2.1.2","status":"affected"}]}],"references":[{"url":"https://github.com/christianhelle/refitter/security/advisories/GHSA-58x9-vjvp-6mx8","name":"https://github.com/christianhelle/refitter/security/advisories/GHSA-58x9-vjvp-6mx8","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/christianhelle/refitter/pull/1178","name":"https://github.com/christianhelle/refitter/pull/1178","tags":["x_refsource_MISC"]},{"url":"https://github.com/christianhelle/refitter/commit/63a19b03699a9c267d6fab5f758ec26484db83a1","name":"https://github.com/christianhelle/refitter/commit/63a19b03699a9c267d6fab5f758ec26484db83a1","tags":["x_refsource_MISC"]},{"url":"https://github.com/christianhelle/refitter/releases/tag/2.1.2","name":"https://github.com/christianhelle/refitter/releases/tag/2.1.2","tags":["x_refsource_MISC"]},{"url":"https://github.com/user-attachments/files/29395048/maintainer-report.txt","name":"https://github.com/user-attachments/files/29395048/maintainer-report.txt","tags":["x_refsource_MISC"]},{"url":"https://github.com/user-attachments/files/29395050/make_spec.py","name":"https://github.com/user-attachments/files/29395050/make_spec.py","tags":["x_refsource_MISC"]},{"url":"https://github.com/user-attachments/files/29395051/reproduce.sh","name":"https://github.com/user-attachments/files/29395051/reproduce.sh","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"ACTIVE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.6,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-94","lang":"en","description":"CWE-94: Improper Control of Generation of Code ('Code Injection')","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-116","lang":"en","description":"CWE-116: Improper Encoding or Escaping of Output","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-30T22:17:02.231Z"},"source":{"advisory":"GHSA-58x9-vjvp-6mx8","discovery":"UNKNOWN"}}}}}