CVE-2026-63346 - Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, the header parameter nam
Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, the header parameter name in `parameters[].name` with `in: header` is emitted verbatim into a Refit `[Header("<name>")]` attribute string without escaping quotation marks. An attacker-influenced OpenAPI description can pass default validation without `--skip-validation` and break out from the parameter-list position by closing the parameter and method syntax, attribute, interface, and namespace. The generated file can remain valid C# while containing a top-level file class with a `[ModuleInitializer]` method, which executes attacker code when the compiled assembly is loaded at application startup, even if the client is never called. Query `AliasAs` and enum/default value sinks are escaped; this flaw is in header-name attribute-string emission. The behavior was verified with Refitter 2.0.0 and .NET 8. This issue is fixed in version 2.1.2.
INFORMATIONAL
Severity & confidence
Source severityinformational
Platform severityinformational
Confidencehigh
Exploitationunknown
CVSS-
Affected
Reporting sources (1)
NIST NVD - National Vulnerability Database
Timeline & provenance
Published2026-10-30T23:17:14
Last updated2026-11-02T23:05:36
Ingested2026-11-02T07:30:40
FreshnessNEAR-REAL-TIME
Threat typevulnerability
Recommended action
No recommended action published with this item - review the original source.
Next steps
- Identify affected systems in your environment.
- Apply the vendor patch or mitigation guidance.
- Review logs for indicators described in the advisory.
- Follow the affected vendor/product to track updates.
Confidence explanation
Reported by a government or cert-grade source (CISA, NCSC, NVD, ENISA, MSRC).
Source type: standards ยท Original: NIST NVD - National Vulnerability Database