Skip to content
OpenAdvisories
Critical · 9.3 CVE-2026-63469 EUVD-2026-116146GHSA-6xmv-cjr5-w3q8

fastapi-code-generator: Import-time RCE via response status-code key -> unescaped @app.get(..., responses={...}) dict

Published Nov 3, 2026 · Updated Nov 9, 2026 · Assigned by GitHub_M

Description

fastapi-code-generator creates FastAPI applications from OpenAPI files. Prior to 0.8.1, the generator inserts an additional response status-code key into the generated responses={...} route-decorator dictionary as a single-quoted Python string without escaping embedded quotes. A multi-response OpenAPI operation with an attacker-controlled or attacker-influenced second non-primary response key can close the dictionary-key literal and inject a valid Python expression. 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 its decorator arguments are evaluated. This additional-response-key sink is distinct from the project's separate route-path and operation-summary sinks. This issue is fixed in version 0.8.1.

Affected products

VendorProductAffectedFixed
koxudaxi fastapi-code-generator < 0.8.1 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI fastapi-code-generator < 0.8.1 0.8.1 GHSA-6xmv-cjr5-w3q8

References