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CVE-1999-0391

21
FAUCET Score

CVE-1999-0391 describes a critical vulnerability in Windows 95, 98, NT, and 2000 where the SMB authentication challenge could be reused. This allowed an attacker to replay a legitimate authentication response, effectively impersonating a user. With a CVSS score of 7.5 (HIGH), this flaw had a low attack complexity and could lead to compromise of confidentiality, integrity, and availability. While no exploit intelligence or community discussion is noted, and it's not on the KEV catalog, the nature of the vulnerability indicates a significant risk if exploited.

Impacted Technologies

VendorProductVersion(s)CPE
All Versions ImpactedCPE matchmatch criteria
cpe:2.3:a:microsoft:terminal_server:*:*:*:*:*:*:*:*
All Versions ImpactedCPE matchmatch criteria
cpe:2.3:o:microsoft:windows_2000:*:*:*:*:*:*:*:*
3.5.1CPE matchmatch criteria
cpe:2.3:o:microsoft:windows_nt:3.5.1:sp1:*:*:*:*:*:*
3.5.1CPE matchmatch criteria
cpe:2.3:o:microsoft:windows_nt:3.5.1:sp2:*:*:*:*:*:*
3.5.1CPE matchmatch criteria
cpe:2.3:o:microsoft:windows_nt:3.5.1:sp3:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

7.5HIGH

AV:N/AC:L/Au:N/C:P/I:P/A:P

Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Exploitability Score
10.0
Impact Score
6.4
CvssVersion
2.0

Exploit Intelligence

EPSS Score
4.89%
Probability of exploitation in next 30 days
EPSS Percentile
91.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0489 is in the 84th percentile among its peer group of 51,485 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

marc.info