CVE-1999-0391: Microsoft Terminal Server

High severity, CVSS 7.5. EPSS: 4.9% chance of exploitation in the next 30 days.

The cryptographic challenge of SMB authentication in Windows 95 and Windows 98 can be reused, allowing an attacker to replay the response and impersonate a user.

Affected products

• Microsoft Terminal Server: any version
• Microsoft Windows 2000: any version
• Microsoft Windows Nt: version 3.5.1 only; version 4.0 only

Published 1999-01-05. Last modified 2026-06-16.