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.

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction Active

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/christianhelle/refitter/commit/ab4d8e439d6f0ee82ad49ee15323978d70fe5a67 cve-icon cve-icon
https://github.com/christianhelle/refitter/pull/1178 cve-icon cve-icon
https://github.com/christianhelle/refitter/releases/tag/2.1.2 cve-icon cve-icon
https://github.com/christianhelle/refitter/security/advisories/GHSA-p32v-8v8j-j534 cve-icon cve-icon
https://github.com/user-attachments/files/29394848/reproduce.sh cve-icon cve-icon
https://github.com/user-attachments/files/29394851/maintainer-report.txt cve-icon cve-icon
https://github.com/user-attachments/files/29394853/make_spec.py cve-icon cve-icon
History

Fri, 30 Oct 2026 22:30:00 +0000

Type Values Removed Values Added
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.
Title Refitter: C# source injection through OpenAPI content-type map keys
Weaknesses CWE-116
CWE-94
References
Metrics cvssV4_0

{'score': 8.6, 'vector': '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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-30T22:15:27.846Z

Reserved: 2026-07-16T14:14:24.385Z

Link: CVE-2026-63344

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-30T23:17:13.840

Modified: 2026-10-30T23:17:13.840

Link: CVE-2026-63344

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-30T23:30:15Z

Weaknesses