CVE-1999-0391

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.

Published: 1999-01-05 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-1999-0391 is rated Moderate Risk (62.2/100): CVSS High severity, with high exploitation likelihood (EPSS 4.89%, 91th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-1999-0391

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 4.50% 4.89% +0.39%
2 2025-12-28 5.04% 4.50% -0.54%
3 2025-12-27 — 5.04% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-1999-0391

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-1999-0391

OS Trackers for CVE-1999-0391

vendor priority summary link
alpine — CVE-1999-0391: no source package rows; 0 state rows across 0 repos (none); fixed 0, open 0. https://security.alpinelinux.org/vuln/CVE-1999-0391

Affected software / configurations for CVE-1999-0391

Vendor Product Version Raw CPE
microsoft terminal_server — cpe:2.3:a:microsoft:terminal_server:*:*:*:*:*:*:*:*
microsoft windows_2000 — cpe:2.3:o:microsoft:windows_2000:*:*:*:*:*:*:*:*
microsoft windows_nt 3.5.1 cpe:2.3:o:microsoft:windows_nt:3.5.1:sp1:*:*:*:*:*:*
microsoft windows_nt 3.5.1 cpe:2.3:o:microsoft:windows_nt:3.5.1:sp2:*:*:*:*:*:*
microsoft windows_nt 3.5.1 cpe:2.3:o:microsoft:windows_nt:3.5.1:sp3:*:*:*:*:*:*
microsoft windows_nt 3.5.1 cpe:2.3:o:microsoft:windows_nt:3.5.1:sp4:*:*:*:*:*:*
microsoft windows_nt 3.5.1 cpe:2.3:o:microsoft:windows_nt:3.5.1:sp5:*:*:*:*:*:*
microsoft windows_nt 4.0 cpe:2.3:o:microsoft:windows_nt:4.0:*:*:*:*:*:*:*
microsoft windows_nt 4.0 cpe:2.3:o:microsoft:windows_nt:4.0:sp1:*:*:*:*:*:*
microsoft windows_nt 4.0 cpe:2.3:o:microsoft:windows_nt:4.0:sp2:*:*:*:*:*:*
microsoft windows_nt 4.0 cpe:2.3:o:microsoft:windows_nt:4.0:sp3:*:*:*:*:*:*
microsoft windows_nt 4.0 cpe:2.3:o:microsoft:windows_nt:4.0:sp4:*:*:*:*:*:*
microsoft windows_nt 4.0 cpe:2.3:o:microsoft:windows_nt:4.0:sp5:*:*:*:*:*:*

References for CVE-1999-0391

cvelogic Threat Intelligence