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: <ct>", "Content-Type: <ct>")]` 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.
History

Tue, 03 Nov 2026 17:00:00 +0000

Type Values Removed Values Added
First Time appeared Christianhelle
Christianhelle refitter
Vendors & Products Christianhelle
Christianhelle refitter

Fri, 30 Oct 2026 22:30:00 +0000

Type Values Removed Values Added
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: <ct>", "Content-Type: <ct>")]` 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.
Title Refitter: C# source injection through OpenAPI content-type map keys
Weaknesses CWE-116
CWE-94
References
Metrics cvssV4_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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-10-30T22:15:27.846Z

Updated: 2026-10-30T22:15:27.846Z

Reserved: 2026-07-16T14:14:24.385Z

Link: CVE-2026-63344

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-30T23:17:13.840

Modified: 2026-11-02T19:35:33.347

Link: CVE-2026-63344

cve-icon Redhat

No data.