CVE-1999-0391

High

Published: 05/01/1999(UTC)Updated: 16/06/2026(UTC)Translated: 17/06/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Very high risk

4.89%

91th percentile - higher than 91% of all known CVEs

Summary

The SMB authentication in Windows 95 and Windows 98 has a vulnerability that allows the cryptographic challenge response to be reused. An attacker can replay this response and impersonate a user.

Risk Assessment

This vulnerability poses a risk of unauthorized access to systems, potentially leading to data theft or other malicious activities.

Recommendation

It is recommended to upgrade systems to newer versions that are not vulnerable to this flaw and to implement additional security measures to protect against replay attacks.

Original NVD description (English source)

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.