CVE-2026-63345CWE-1116CWE-94code-injection

Refitter: C# source injection through OpenAPI path keys

High · published October 30, 2026

CVSS v4.0
8.6
EPSS
—
In the wild
Unconfirmed
What it is

Refitter is a tool for generating a C# REST API client using the Refit library. Prior to 2.1.2, OpenAPI `paths`-object keys are emitted verbatim into Refit route attributes such as `[Get("<path>")]` without escaping quotation marks or restricting characters. An attacker-influenced single-line, slash-prefixed path survives default validation without `--skip-validation` and can close the attribute string, interface, and namespace while introducing a top-level file class and reopening the generated structure to keep valid C#. A `[ModuleInitializer]` method executes attacker code when an application compiles and loads the generated assembly at startup, even without calling the generated client. The enum and default value sinks are escaped and are not the vulnerable path-emission sink. The behavior was verified on Refitter 2.0.0 with .NET 8. This issue is fixed in version 2.1.2.

The record
Technical detail
CVSS v4.0
8.6 · HIGH
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
EPSS
Not scored
Weaknesses
CWE-1116 · Inaccurate Source Code Comments; CWE-94 · Improper Control of Generation of Code ('Code Injection')
Published
2026-10-30T22:13Z
Timeline
  • 30 OCT 22:13Z
    Refitter: C# source injection through OpenAPI path keys
    cvelistv5
  • 30 OCT 22:13Z
    Refitter: C# source injection through OpenAPI path keys
    cvelistv5