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CVE-2024-40627GHSA-5F5C-8RVC-J8WFPYSEC-2026-1361

OpaMiddleware does not filter HTTP OPTIONS requests

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 2.0.1
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: poc
  • Automatable: yes
  • Technical impact: partial

Summary

Fastapi OPA is an opensource fastapi middleware which includes auth flow. HTTP `OPTIONS` requests are always allowed by `OpaMiddleware`, even when they lack authentication, and are passed through directly to the application. `OpaMiddleware` allows all HTTP `OPTIONS` requests without evaluating it against any policy. If an application provides different responses to HTTP `OPTIONS` requests based on an entity existing (such as to indicate whether an entity is writable on a system level), an unauthenticated attacker could discover which entities exist within an application. This issue has been addressed in release version 2.0.1. All users are advised to upgrade. There are no known workarounds for this vulnerability.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • busykoala fastapi-opa

    fixed in 2.0.1

  • fastapi-opaPyPI

    fixed in 2.0.1

References 3

GitHub · busykoala/fastapi-opa