CVE-2026-63344
Published:October 30, 2026
Updated:November 03, 2026
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.
Affected Packages
Refitter.Core (DOT_NET):
Affected version(s) >=0.2.1.0 <2.1.2 || >=1.0.0.0 <2.1.2 || >=2.0.0.0 <2.1.2Fix Suggestion:
Update to version 2.1.2https://github.com/christianhelle/refitter.git (GITHUB):
Affected version(s) >=0.1.3-alpha <2.1.2 || >=1.0.0 <2.1.2 || >=2.0.0 <2.1.2Fix Suggestion:
Update to version 2.1.2refitter (NUGET):
Affected version(s) >=0.1.2-alpha <2.1.2 || >=1.0.0 <2.1.2 || >=2.0.0 <2.1.2Fix Suggestion:
Update to version 2.1.2refitter.core (NUGET):
Affected version(s) >=0.2.1-alpha <2.1.2 || >=1.0.0 <2.1.2 || >=2.0.0 <2.1.2Fix Suggestion:
Update to version 2.1.2Related Resources (9)
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Contact UsCVSS v4
Base Score:
8.6
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
ACTIVE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.8
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
EPSS
Base Score:
0.35