CVE-1999-1591: Microsoft Internet Information Services (IIS) server 4.0 SP4, without certain hotfixes released for SP4, does not requir

Published n/a Updated 2026-08-21T04:30:53.669Z

Summary

Microsoft Internet Information Services (IIS) server 4.0 SP4, without certain hotfixes released for SP4, does not require authentication credentials under certain conditions, which allows remote attackers to bypass authentication requirements, as demonstrated by connecting via Microsoft Visual InterDev 6.0.

Severity

UNKNOWN

Source Attribution

Source: NVD · Updated: 2026-08-21T04:30:53.669Z · Confidence: high

Impact

Based on CVSS vector: n/a — assess confidentiality, integrity, and availability impact via the official vector documentation.

Affected Software

Fix

Upgrade affected software to the fixed version identified above. Apply vendor patches and monitor advisories before exposed systems go unpatched.

References