Nearly 11 Million SMTP Port 587 Endpoints Found Exposed Online

A ZoomEye query for port 587 and the SMTP service fingerprint returned 10,990,138 records on September 26, 2026. Port 587 exists for authenticated mail submission, so the number of publicly reachable endpoints warrants review.

• Query port=587 && service="smtp" returned 10,990,138 records
• Data collected on 2026-09-26 at 02:43 UTC
• Count includes honeypots and short-lived hosts
• Authentication on each port is the only barrier to sending mail from the domain