CVE-2026-63344
Refitter: C# source injection through OpenAPI content-type map keys
- State
- Published
- Severity
- 8.6 High
- Published
- Oct 30, 2026
- Updated
- Oct 30, 2026
- Reserved
- Jul 16, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.6 High | 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 | GitHub_M |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
refitterchristianhelle |
|
References
- https://github.com/christianhelle/refitter/security/advisories/GHSA-p32v-8v8j-j534
- https://github.com/christianhelle/refitter/pull/1178
- https://github.com/christianhelle/refitter/commit/ab4d8e439d6f0ee82ad49ee15323978d70fe5a67
- https://github.com/christianhelle/refitter/releases/tag/2.1.2
- https://github.com/user-attachments/files/29394848/reproduce.sh
- https://github.com/user-attachments/files/29394851/maintainer-report.txt
- https://github.com/user-attachments/files/29394853/make_spec.py
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