Vulnerability details

CVE-2026-63471

koxudaxi fastapi-code-generator

fastapi-code-generator: Import-time RCE via route path -> unescaped @app.get('...') decorator

CVSS 4.0
9.3Critical

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.

CVSS scores

ScoreVersionSourceVector
9.3Critical 4.0 CVEProject cvelistV5 (CNA) (GitHub_M) 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

Affected products

VendorProductVersionsSource
koxudaxi fastapi-code-generator < 0.8.1 CVEProject cvelistV5 (CNA)

References and advisories

4
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Details

Published
2026-11-03
Last updated
2026-11-07
State
Published
Assigner (CNA)
GitHub_M
Kolun priority
20 · Low

Exploit prediction (EPSS)

0.31%
Probability of exploitation in 30 days
24.2%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
Yes
Exploitation
Proof of concept
Technical impact
Total

Weaknesses (CWE)

  • CWE-94
    Improper Control of Generation of Code ('Code Injection')
  • CWE-116
    Improper Encoding or Escaping of Output