Paper/Archive/CVE-2026-63470

CVE-2026-63470

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

Description · from the CVE record

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

ProductAffectedFixed inSource
fastapi-code-generator< 0.8.1–CNA

Scores by source

GitHub_M (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: total

References

exploitgithub.com/koxudaxi/fastapi-code-generator/security/advisories/GHSA-h667-4jj2-cgv4refgithub.com/koxudaxi/fastapi-code-generator/commit/49301dbdb82170d7f50877419d994b05cb1fa2bcrefgithub.com/koxudaxi/fastapi-code-generator/commit/b3b9bd66e0b0c4d8c686fda700258104615a1332refgithub.com/koxudaxi/fastapi-code-generator/releases/tag/0.8.1