{"id":"CVE-2026-63346","aliases":["EUVD-2026-114540","GHSA-58x9-vjvp-6mx8"],"status":"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(\"\u003cname\u003e\")]` 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.","severity":{"version":"4.0","score":8.6,"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.0035,"percentile":0.29112,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-116","CWE-94"],"published":"2026-10-30T22:17:02Z","modified":"2026-11-04T02:30:48Z","products":[{"vendor":"christianhelle","product":"refitter"}],"references":[{"url":"https://github.com/christianhelle/refitter/security/advisories/GHSA-58x9-vjvp-6mx8","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/christianhelle/refitter/pull/1178","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/christianhelle/refitter/commit/63a19b03699a9c267d6fab5f758ec26484db83a1","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/christianhelle/refitter/releases/tag/2.1.2","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/user-attachments/files/29395048/maintainer-report.txt","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/user-attachments/files/29395050/make_spec.py","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/user-attachments/files/29395051/reproduce.sh","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63346.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63346","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-63346","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(\"\u003cname\u003e\")]` 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.","status":"published","published":"2026-10-30T22:17:02.231Z","modified":"2026-11-02T14:47:20.841Z","cvss":[{"version":"4.0","score":8.6,"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","level":"high","assessor":"cna"}],"cwes":["CWE-94","CWE-116"],"updated_at":"2026-11-02T18:00:08.034842Z"}],"euvd":[{"id":"EUVD-2026-114540","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(\"\u003cname\u003e\")]` 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.","status":"published","published":"2026-10-30T22:17:02Z","modified":"2026-11-02T14:47:20Z","cvss":[{"version":"4.0","score":8.6,"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","level":"high"}],"updated_at":"2026-11-02T16:58:44.835214Z"}],"nvd":[{"id":"CVE-2026-63346","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(\"\u003cname\u003e\")]` 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.","status":"published","published":"2026-10-30T23:17:14.13Z","modified":"2026-11-02T19:35:33.347Z","cvss":[{"version":"4.0","score":8.6,"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/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"}],"cwes":["CWE-94","CWE-116"],"updated_at":"2026-11-03T00:02:42.364722Z"}],"osv":[{"id":"CVE-2026-63346","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(\"\u003cname\u003e\")]` 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.","status":"published","published":"2026-10-30T22:17:02.231Z","modified":"2026-11-04T02:30:48.878967555Z","cvss":[{"version":"4.0","score":8.6,"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","level":"high"}],"cwes":["CWE-116","CWE-94"],"updated_at":"2026-11-04T02:54:44.889498Z"}]}}