{"id":"CVE-2026-63344","aliases":["EUVD-2026-114539","GHSA-p32v-8v8j-j534"],"status":"published","title":"Refitter: C# source injection through OpenAPI content-type map keys","description":"Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, content-type keys in the content maps of `requestBody/responses` are emitted verbatim into a Refit `[Headers(\"Accept: \u003cct\u003e\", \"Content-Type: \u003cct\u003e\")]` attribute string without escaping quotation marks. A crafted content-type key in an attacker-influenced OpenAPI description survives default validation without `--skip-validation`, breaks out of the attribute string and enclosing interface and namespace, and can introduce a top-level file class while leaving valid generated C#. A `[ModuleInitializer]` method in that class executes attacker code when the generated assembly is loaded at application startup, without requiring a call to the client. 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":"2026-11-11","score":0.0035,"percentile":0.2907,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-116","CWE-94"],"published":"2026-10-30T22:15:27Z","modified":"2026-11-06T18:49:39Z","products":[{"vendor":"christianhelle","product":"refitter"}],"references":[{"url":"https://github.com/christianhelle/refitter/security/advisories/GHSA-p32v-8v8j-j534","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/ab4d8e439d6f0ee82ad49ee15323978d70fe5a67","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/29394848/reproduce.sh","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/user-attachments/files/29394851/maintainer-report.txt","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/user-attachments/files/29394853/make_spec.py","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63344.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63344","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-63344","title":"Refitter: C# source injection through OpenAPI content-type map keys","description":"Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, content-type keys in the content maps of `requestBody/responses` are emitted verbatim into a Refit `[Headers(\"Accept: \u003cct\u003e\", \"Content-Type: \u003cct\u003e\")]` attribute string without escaping quotation marks. A crafted content-type key in an attacker-influenced OpenAPI description survives default validation without `--skip-validation`, breaks out of the attribute string and enclosing interface and namespace, and can introduce a top-level file class while leaving valid generated C#. A `[ModuleInitializer]` method in that class executes attacker code when the generated assembly is loaded at application startup, without requiring a call to the client. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2.","status":"published","published":"2026-10-30T22:15:27.846Z","modified":"2026-11-06T18:49:39.123Z","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":"2026-11-06T19:59:20.130638Z"}],"euvd":[{"id":"EUVD-2026-114539","description":"Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, content-type keys in the content maps of `requestBody/responses` are emitted verbatim into a Refit `[Headers(\"Accept: \u003cct\u003e\", \"Content-Type: \u003cct\u003e\")]` attribute string without escaping quotation marks. A crafted content-type key in an attacker-influenced OpenAPI description survives default validation without `--skip-validation`, breaks out of the attribute string and enclosing interface and namespace, and can introduce a top-level file class while leaving valid generated C#. A `[ModuleInitializer]` method in that class executes attacker code when the generated assembly is loaded at application startup, without requiring a call to the client. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2.","status":"published","published":"2026-10-30T22:15:27Z","modified":"2026-11-06T18:49:39Z","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":"2026-11-06T20:06:05.664912Z"}],"nvd":[{"id":"CVE-2026-63344","description":"Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, content-type keys in the content maps of `requestBody/responses` are emitted verbatim into a Refit `[Headers(\"Accept: \u003cct\u003e\", \"Content-Type: \u003cct\u003e\")]` attribute string without escaping quotation marks. A crafted content-type key in an attacker-influenced OpenAPI description survives default validation without `--skip-validation`, breaks out of the attribute string and enclosing interface and namespace, and can introduce a top-level file class while leaving valid generated C#. A `[ModuleInitializer]` method in that class executes attacker code when the generated assembly is loaded at application startup, without requiring a call to the client. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2.","status":"published","published":"2026-10-30T23:17:13.84Z","modified":"2026-11-06T19:17:55.31Z","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":"2026-11-06T22:02:15.900703Z"}],"osv":[{"id":"CVE-2026-63344","title":"Refitter: C# source injection through OpenAPI content-type map keys","description":"Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, content-type keys in the content maps of `requestBody/responses` are emitted verbatim into a Refit `[Headers(\"Accept: \u003cct\u003e\", \"Content-Type: \u003cct\u003e\")]` attribute string without escaping quotation marks. A crafted content-type key in an attacker-influenced OpenAPI description survives default validation without `--skip-validation`, breaks out of the attribute string and enclosing interface and namespace, and can introduce a top-level file class while leaving valid generated C#. A `[ModuleInitializer]` method in that class executes attacker code when the generated assembly is loaded at application startup, without requiring a call to the client. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2.","status":"published","published":"2026-10-30T22:15:27.846Z","modified":"2026-11-08T02:30:35.117168202Z","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":"2026-11-07T11:15:41.683306Z"}]}}