---
id: CVE-2026-63469
title: >-
  fastapi-code-generator: Import-time RCE via response status-code key ->
  unescaped @app.get(..., responses={...}) dict
summary: >-
  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 …
severity: critical
cvss: 9.3
cvssVector: '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'
cvssSource: cna
cwe:
  - CWE-94
  - CWE-116
vendor: koxudaxi
product: fastapi-code-generator
affected:
  - fastapi-code-generator < 0.8.1
published: '2026-11-03'
updated: '2026-11-03'
sourceUpdated: '2026-11-03T19:15:54.707Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-63469'
references:
  - url: >-
      https://github.com/koxudaxi/fastapi-code-generator/security/advisories/GHSA-6xmv-cjr5-w3q8
    label: >-
      https://github.com/koxudaxi/fastapi-code-generator/security/advisories/GHSA-6xmv-cjr5-w3q8
  - url: >-
      https://github.com/koxudaxi/fastapi-code-generator/commit/49301dbdb82170d7f50877419d994b05cb1fa2bc
    label: >-
      https://github.com/koxudaxi/fastapi-code-generator/commit/49301dbdb82170d7f50877419d994b05cb1fa2bc
  - url: >-
      https://github.com/koxudaxi/fastapi-code-generator/commit/b3b9bd66e0b0c4d8c686fda700258104615a1332
    label: >-
      https://github.com/koxudaxi/fastapi-code-generator/commit/b3b9bd66e0b0c4d8c686fda700258104615a1332
  - url: 'https://github.com/koxudaxi/fastapi-code-generator/releases/tag/0.8.1'
    label: 'https://github.com/koxudaxi/fastapi-code-generator/releases/tag/0.8.1'
tags:
  - cve.org
epss: 0.00312
epssPercentile: 0.24264
ingestedAt: '2026-11-05T20:33:06.394Z'
---

## Overview

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

- `fastapi-code-generator < 0.8.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.