Vulnerability · Published Nov 3, 2026 · Assigned by GitHub_M
CVE-2026-63471fastapi-code-generator: Import-time RCE via route path -> unescaped @app.get('...') decorator
Critical 9.3
In plain English
A critical-severity code injection in fastapi-code-generator from koxudaxi. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| koxudaxi | fastapi-code-generator | < 0.8.1 |
Weakness: CWE-94, CWE-116 · 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
References
- https://github.com/koxudaxi/fastapi-code-generator/security/advisories/GHSA-p2mm-64f6-gmpp x_refsource_CONFIRM
- https://github.com/koxudaxi/fastapi-code-generator/commit/49301dbdb82170d7f50877419d994b05cb1fa2bc x_refsource_MISC
- https://github.com/koxudaxi/fastapi-code-generator/commit/b3b9bd66e0b0c4d8c686fda700258104615a1332 x_refsource_MISC
- https://github.com/koxudaxi/fastapi-code-generator/releases/tag/0.8.1 x_refsource_MISC