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Critical · 9.3 CVE-2026-63470 EUVD-2026-116145GHSA-h667-4jj2-cgv4

fastapi-code-generator: Call-time RCE via operation summary -> unescaped route-handler docstring

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

Description

fastapi-code-generator creates FastAPI applications from OpenAPI files. Prior to 0.8.1, the generator inserts Operation.summary into a generated route-handler docstring as a triple-double-quoted string without escaping embedded triple quotes. An attacker-controlled or attacker-influenced operation summary can close the docstring and inject a valid Python expression statement into the handler body. Syntax-breaking input only causes generation to fail, but syntactically valid generated code executes with the server process's privileges when the affected route handler is called. This call-time route-handler docstring sink is distinct from the project's separate import-time route-path and additional-response-key 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-h667-4jj2-cgv4

References