CVE-2026-63471 PUBLISHED

fastapi-code-generator: Import-time RCE via route path -> unescaped @app.get('...') decorator

Assigner: GitHub_M
Reserved: 16.07.2026 Published: 03.11.2026 Updated: 03.11.2026

fastapi-code-generator creates FastAPI applications from OpenAPI files. Prior to 0.8.1, the generator inserts an OpenAPI path into a generated @app.get(...) route decorator as a single-quoted generated route string without escaping embedded quotes. An attacker-controlled or attacker-influenced OpenAPI path can close the string and inject a valid Python expression into the decorator argument. Syntax-breaking input only causes generation to fail, but syntactically valid generated code executes with the application's or CI process's privileges when the generated module is imported and the decorator is evaluated. This OpenAPI path sink is distinct from the project's separate operation-summary docstring and additional-response-key sinks. This issue is fixed in version 0.8.1.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 9.3

Product Status

Vendor koxudaxi
Product fastapi-code-generator
Versions
  • Version < 0.8.1 is affected

References

Problem Types

  • CWE-94: Improper Control of Generation of Code ('Code Injection') CWE
  • CWE-116: Improper Encoding or Escaping of Output CWE