Cloudfront return 403 on OPTION request

Question

I have a cloudfront distribution pointing to S3.

Accessing to de URL directly works fine.

But is part o a complex API, de API return a 307 that points to the cloudfront, and the webbrowser made and and OPTIONS request.

The OPTIONS return a 403

The distributions contains a single behavior and accepts GET, HEAD, OPTIONS, PUT, POST, PATCH, DELETE

I have tested several combinations of CORS response headers but none works.
This is my current configuration

![current configuration](/media/postImages/original/IMJoNYciw4RIqEBUrNuTbpPw)

any idea about why cloudfront returns a 403?

Accepted Answer

It seems like the OPTIONS request is being blocked either due to incorrect CORS configuration or WAF rules blocking the request. A few things to check:

Verify that the CORS configuration on the S3 bucket allows the Origin, Access-Control-Request-Method and Access-Control-Request-Headers that are being sent in the OPTIONS request.

Check if a WAF web ACL is associated with the CloudFront distribution and blocking the OPTIONS request. The WAF rules need to allow OPTIONS requests to pass through.

Make sure the CloudFront distribution behavior allows OPTIONS method.

Try simplifying the CORS configuration on S3 to just allow all origins, methods and headers as a test:

```

[
  {
    "AllowedHeaders": ["*"],
    "AllowedMethods": ["GET","PUT","POST","DELETE","HEAD","OPTIONS"], 
    "AllowedOrigins": ["*"],
    "ExposeHeaders": []
  }
]
```

Check CloudFront and S3 access logs to see exactly what requests are reaching the origin and getting blocked.

Cloudfront return 403 on OPTION request

관련 콘텐츠