How severe is CVE-2018-3991?

CVE-2018-3991 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-3991 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 34% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-3991?

CVE-2018-3991 primarily affects Wibu Wibukey. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-3991?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2018-3991 published?

CVE-2018-3991 was published on 2019-02-05 and last updated on 2026-06-17.

CVE-2018-3991

CVE-2018-3991 is a critical-severity vulnerability in Wibu Wibukey with a CVSS 3.x base score of 10.0. Its EPSS exploit-prediction score of 34% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
CVSS v2: 7.5
EPSS exploit prediction: 34% (98th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Wibu Wibukey
Published: 2019-02-05
Last modified: 2026-06-17

Description

An exploitable heap overflow vulnerability exists in the WkbProgramLow function of WibuKey Network server management, version 6.40.2402.500. A specially crafted TCP packet can cause a heap overflow, potentially leading to remote code execution. An attacker can send a malformed TCP packet to trigger this vulnerability.

Frequently asked questions

What is CVE-2018-3991?: An exploitable heap overflow vulnerability exists in the WkbProgramLow function of WibuKey Network server management, version 6.40.2402.500. A specially crafted TCP packet can cause a heap overflow, potentially leading to remote code execution. An attacker can send a malformed TCP packet to trigger this vulnerability.
How severe is CVE-2018-3991?: CVE-2018-3991 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-3991 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 34% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-3991?: CVE-2018-3991 primarily affects Wibu Wibukey. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-3991?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2018-3991 published?: CVE-2018-3991 was published on 2019-02-05 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:wibu:wibukey:6.40.2402.500:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_wincc_open_architecture:3.14:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_wincc_open_architecture:3.15:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_wincc_open_architecture:3.16:*:*:*:*:*:*:*

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