CVE-2026-63184
Refitter: Unrestricted OpenAPI references permit build-host SSRF and file inclusion
Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.1, the `refitter` dotnet tool invokes `NJsonSchema` with unsafe defaults for `$ref` resolution when generating Refit interfaces and contracts from attacker-controlled or attacker-influenced OpenAPI descriptions. Remote `http(s)` references cause requests from the developer or CI host and inline untrusted remote schema content into generated output. Absolute local file paths and relative `../` traversal outside the input directory also resolve and inline local content, permitting arbitrary local-file disclosure. The demonstrated chain stops at server-side request forgery, remote file inclusion, and local file inclusion, not code execution: Refit sets the base URL at runtime, enum values use verbatim-string doubling, and string defaults are escaped. This issue is fixed in version 2.1.1.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| refitter christianhelle |
< 2.1.1 (affected) | CNA: GitHub_M |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 7.1 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N | CNA: GitHub_M |
Exploit evidence
- https://github.com/christianhelle/refitter/security/advisories/GHSA-x6w4-f264-3vvr
exploit · ADP: CISA-ADP
References
- https://github.com/christianhelle/refitter/security/advisories/GHSA-x6w4-f264-3vvrCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/christianhelle/refitter/pull/1173CNA: GitHub_M · x_refsource_MISC
- https://github.com/christianhelle/refitter/commit/6ad20a3803561225100b0a4bb6b12f947d23db7bCNA: GitHub_M · x_refsource_MISC
- https://github.com/christianhelle/refitter/releases/tag/2.1.1CNA: GitHub_M · x_refsource_MISC
- https://github.com/user-attachments/files/29395269/reproduce.shCNA: GitHub_M · x_refsource_MISC
- https://github.com/user-attachments/files/29395271/maintainer-report.txtCNA: GitHub_M · x_refsource_MISC
- https://github.com/user-attachments/files/29395272/advisory.mdCNA: GitHub_M · x_refsource_MISC
- https://github.com/user-attachments/files/29395283/reproduce.shCNA: GitHub_M · x_refsource_MISC
- https://github.com/user-attachments/files/29395284/maintainer-report.txtCNA: GitHub_M · x_refsource_MISC
- https://github.com/user-attachments/files/29395285/advisory.mdCNA: GitHub_M · x_refsource_MISC
- https://github.com/user-attachments/files/29395286/listener.pyCNA: GitHub_M · x_refsource_MISC
- https://github.com/user-attachments/files/29395288/make_spec.pyCNA: GitHub_M · x_refsource_MISC
- https://github.com/christianhelle/refitter/security/advisories/GHSA-x6w4-f264-3vvrADP: CISA-ADP · exploit
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