GHSA-qmv4-jgp7-mf68

Affected versions of `sails` have an issue with the CORS configuration where the value of the origin header is reflected as the value for the `Access-Control-Allow-Origin` header. This may allow an attacker to make AJAX requests to vulnerable hosts through cross-site scripting or a malicious HTML Document, effectively bypassing the Same Origin Policy.

## Mitigating Factors

This is only an issue when `allRoutes` is set to `true` and `origin` is set to `*` or left commented out in the sails CORS config file.

The problem can be compounded when the cors `credentials` setting is not provided, because at that point authenticated cross domain requests are possible.

## Recommendation

Update to version 0.12.7 or later.

As this vulnerability is primarily a user error, the patch for the vulnerability will simply cause the application to write an error message to the console when a vulnerable configuration is used in a production environment.

Writing a proper CORS configuration is still the responsibility of the user, so it is necessary to check for the error message after installing the patch. Be sure you are not using `allRoutes: true` with `origin:'*'`, and that you uncomment `origin` and set it to a reasonable value. Ensure that if `origin` is set to `*` that you truly mean for all other websites to be able to make cross-domain requests to your API.

Likewise, ensure `credentials` is uncommented out and set to the appropriate value. Make sure to explicitly set which origins may request resources via CORS.