CVE-1999-1233: Microsoft Internet Information Server

High severity, CVSS 7.5. EPSS: 5.5% chance of exploitation in the next 30 days.

IIS 4.0 does not properly restrict access for the initial session request from a user's IP address if the address does not resolve to a DNS domain, aka the "Domain Resolution" vulnerability.

Affected products

• Microsoft Internet Information Server: version 4.0 only

Published 1999-12-31. Last modified 2026-06-16.