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CVE-2018-3991

47
FAUCET Score

CVE-2018-3991 is a critical heap overflow vulnerability in the WibuKey Network server management, version 6.40.2402.500, affecting various products including Siemens SIMATIC WinCC Open Architecture and WibuKey. An unauthenticated attacker can trigger this flaw by sending a specially crafted TCP packet, potentially leading to remote code execution with a CVSS score of 9.8 (CRITICAL). While there are no known public exploits in Metasploit, Nuclei, or ExploitDB, the vulnerability has garnered significant community discussion and media coverage, indicating high awareness. Despite its high EPSS and FAUCET Risk Score, it is not currently listed on CISA's KEV catalog.

Impacted Technologies

VendorProductVersion(s)CPE
6.40.2402.500CPE matchmatch criteria
cpe:2.3:a:wibu:wibukey:6.40.2402.500:*:*:*:*:*:*:*
3.14CPE matchmatch criteria
cpe:2.3:o:siemens:simatic_wincc_open_architecture:3.14:*:*:*:*:*:*:*
3.15CPE matchmatch criteria
cpe:2.3:o:siemens:simatic_wincc_open_architecture:3.15:*:*:*:*:*:*:*
3.16CPE matchmatch criteria
cpe:2.3:o:siemens:simatic_wincc_open_architecture:3.16:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

10.0CRITICAL

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
6.0
CvssVersion
3.0

Exploit Intelligence

EPSS Score
34.33%
Probability of exploitation in next 30 days
EPSS Percentile
98.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.3433 is in the 95th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

cert-portal.siemens.com / productcert/pdf/ssa-760124.pdf
MitigationThird Party Advisory
cert-portal.siemens.com / productcert/pdf/ssa-844562.pdf
Third Party Advisory
cert-portal.siemens.com / productcert/pdf/ssa-902727.pdf
talosintelligence.com / vulnerability_reports/TALOS-2018-0659
ExploitThird Party Advisory
securityfocus.com / bid/107005
Third Party AdvisoryVDB Entry