What it is

Access-Control-Allow-Origin is set to * (any site). This lets ANY other website's JavaScript read responses from this domain in the visitor's browser — fine for a public API, risky if any response here ever contains private data.

How to fix it

Restrict Access-Control-Allow-Origin to the specific domains that legitimately need it, instead of *. If you're not sure how, install the WordPress Plugin: its Security tab applies fixes like this one automatically.

In depth

Your website is currently set up to allow any website on the internet to read data from your site when someone visits it in their browser. Think of it like leaving your front door unlocked so anyone can walk in and look around whenever they want. This is usually harmless if your site only shows public information like blog posts, but it becomes a serious problem if any part of your site displays private data like customer information, email addresses, or payment details that a visitor's browser might access. The fix is to tell your website to only allow specific trusted websites to read this data instead of allowing everyone. You can do this by installing a security plugin designed for WordPress, which will automatically change this setting from "allow everyone" to "allow only these specific sites I trust." Most site owners never need this feature enabled at all, so if you're unsure whether you actually use it, your plugin can safely turn it off for you.