Vulnerability Description
Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, OpenAPI `paths`-object keys are emitted verbatim into Refit route attributes such as `[Get("<path>")]` without escaping quotation marks or restricting characters. An attacker-influenced single-line, slash-prefixed path survives default validation without `--skip-validation` and can close the attribute string, interface, and namespace while introducing a top-level file class and reopening the generated structure to keep valid C#. A `[ModuleInitializer]` method executes attacker code when an application compiles and loads the generated assembly at startup, even without calling the generated client. The enum and default value sinks are escaped and are not the vulnerable path-emission sink. The behavior was verified on Refitter 2.0.0 with .NET 8. This issue is fixed in version 2.1.2.
Related Weaknesses (CWE)
References
- https://github.com/christianhelle/refitter/commit/793d2632899c2022511dfc15e30725
- https://github.com/christianhelle/refitter/pull/1178
- https://github.com/christianhelle/refitter/releases/tag/2.1.2
- https://github.com/christianhelle/refitter/security/advisories/GHSA-3fhm-p725-h3
- https://github.com/user-attachments/files/29395228/maintainer-report.txt
- https://github.com/user-attachments/files/29395229/make_spec.py
- https://github.com/user-attachments/files/29395230/reproduce.sh
FAQ
What is CVE-2026-63345?
CVE-2026-63345 is a documented vulnerability. Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, OpenAPI `paths`-object keys are emitted verbatim into Refit route attributes such as `[Get("<path>")]` w...
How severe is CVE-2026-63345?
CVSS scoring is not yet available for CVE-2026-63345. Check NVD for updates.
Is there a patch for CVE-2026-63345?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.