CVE-1999-0419

Medium severity, CVSS 5.0. EPSS: 1.4% chance of exploitation in the next 30 days.

When the Microsoft SMTP service attempts to send a message to a server and receives a 4xx error code, it quickly and repeatedly attempts to redeliver the message, causing a denial of service.

Published 1999-03-01. Last modified 2026-06-16.