CVE-2026-63346

Refitter: C# source injection through OpenAPI header parameter names

State
Published
Severity
8.6 High
Published
Oct 30, 2026
Updated
Oct 30, 2026
Reserved
Jul 16, 2026

Read the record on cve.org

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.

Scores

CVSSScoreVectorSource
4.08.6 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NGitHub_M

Weaknesses

  • CWE-94 Improper Control of Generation of Code ('Code Injection')
  • CWE-116 Improper Encoding or Escaping of Output

Affected Products

ProductVersions
refitterchristianhelle
  • < 2.1.2Affected

References

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