# CVE-2026-63184: Refitter: Unrestricted OpenAPI references permit build-host SSRF and file inclusion

Status: published. Published: 2026-10-30. Updated: 2026-11-02.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- christianhelle / refitter: < 2.1.1 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 7.1 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: 0.41% as of 2026-11-02; percentile 35.38%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-829, CWE-918

## Exploit evidence

- exploit: https://github.com/christianhelle/refitter/security/advisories/GHSA-x6w4-f264-3vvr (ADP: CISA-ADP)

## References

- https://github.com/christianhelle/refitter/security/advisories/GHSA-x6w4-f264-3vvr (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/christianhelle/refitter/pull/1173 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/christianhelle/refitter/commit/6ad20a3803561225100b0a4bb6b12f947d23db7b (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/christianhelle/refitter/releases/tag/2.1.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/user-attachments/files/29395269/reproduce.sh (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/user-attachments/files/29395271/maintainer-report.txt (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/user-attachments/files/29395272/advisory.md (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/user-attachments/files/29395283/reproduce.sh (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/user-attachments/files/29395284/maintainer-report.txt (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/user-attachments/files/29395285/advisory.md (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/user-attachments/files/29395286/listener.py (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/user-attachments/files/29395288/make_spec.py (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/christianhelle/refitter/security/advisories/GHSA-x6w4-f264-3vvr (ADP: CISA-ADP; exploit)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-63184; retrieved 2026-11-02; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-63184; retrieved 2026-11-02; source updated Not reported

Revision: 6cdaded4f28c4dea93d3fd72c3716dc67dcd442b38ed9c3969a0d0a73f9e972b

Canonical: https://y2.dev/cve/CVE-2026-63184

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.