A subdomain points at an unclaimed cloud service and can be taken over

A subdomain takeover happens when a DNS record for a subdomain, like promo.yourdomain.com, still points at a cloud service, such as a hosting platform or CDN, that the business no longer actually owns or has deleted, leaving that DNS record dangling. This check found a subdomain with such a dangling record, confirmed by that service's own distinctive 'not claimed' response. Anyone can register the now-unclaimed cloud resource the dangling DNS record still points to, and once they do, they can serve their own content on the subdomain, which still appears to belong to the business. This is used for convincing phishing pages, stealing session cookies or login credentials tied to the parent domain, and spoofing email that appears to come from the domain. It's consistently one of the top findings in any serious security assessment. Your developer should either remove the dangling DNS record entirely if the subdomain isn't needed, or re-point it to a service the business actually still owns and controls. This should be treated as urgent, since the window between discovery and someone else claiming the resource can be very short.