OpaMiddleware does not filter HTTP OPTIONS requests
Published Jul 15, 2024 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
OpaMiddleware does not filter HTTP OPTIONS requests
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
HTTP OPTIONS requests are always allowed by OpaMiddleware, even when they lack authentication, and are passed through directly to the application. The maintainer uncertain whether this should be classed as a "bug" or "security issue" – but is erring on the side of "security issue" as an application could reasonably assume OPA controls apply to all HTTP methods, and it bypasses more sophisticated policies.
Technical context
OpaMiddleware allows all HTTP OPTIONS requests without evaluating it against any policy: https://github.com/busykoala/fastapi-opa/blob/6dd6f8c87e908fe080784a74707f016f1422b58a/fastapiopa/opa/opamiddleware.pyL79-L80 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 (CWE-204).
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- LOW
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
Record history
Published Jul 15, 2024 · Last refreshed Nov 3, 2026