Adding localhost to Hosted UI -> callback URLs for testing. Security risks?

Amazon Cognito requires HTTPS over HTTP except for http://localhost for testing purposes only. In my development environment, which is also used for early user testing to get feedback, I am using http://localhost as well as the development domain. I am using google authentication through cognito. My question is, is there are security risk in having localhost as a callback URL that could give an attacker some ability to pose any risk to my development environment? if so, what is the best way to address this?