christianhelle Refitter up to 2.1.1 Header Parameter Name name initialization

Summaryinfo

A vulnerability, which was classified as critical, has been found in christianhelle Refitter up to 2.1.1. This affects an unknown function of the component Header Parameter Name. The manipulation of the argument Name leads to initialization. This vulnerability is uniquely identified as CVE-2026-63346. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in christianhelle Refitter up to 2.1.1. This issue affects an unknown functionality of the component Header Parameter Name. The manipulation of the argument name with an unknown input leads to a initialization vulnerability. Using CWE to declare the problem leads to CWE-665. The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-63346 since 07/16/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

Upgrading to version 2.1.2 eliminates this vulnerability.

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Productinfo

Vendor

• christianhelle

Name

• Refitter

Version

• 2.1.0
• 2.1.1

Website

• Product: https://github.com/christianhelle/refitter/

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