How severe is CVE-2015-3991?

CVE-2015-3991 has a CVSS 3.x base score of 9.8, 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-2015-3991 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-3991?

CVE-2015-3991 primarily affects Strongswan. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2015-3991?

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-2015-3991 published?

CVE-2015-3991 was published on 2017-09-07 and last updated on 2026-06-17.

CVE-2015-3991

CVE-2015-3991 is a critical-severity vulnerability in Strongswan with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-19.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 5% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-19
Affected product: Strongswan
Published: 2017-09-07
Last modified: 2026-06-17

Description

strongSwan 5.2.2 and 5.3.0 allows remote attackers to cause a denial of service (daemon crash) or execute arbitrary code.

Frequently asked questions

What is CVE-2015-3991?: strongSwan 5.2.2 and 5.3.0 allows remote attackers to cause a denial of service (daemon crash) or execute arbitrary code.
How severe is CVE-2015-3991?: CVE-2015-3991 has a CVSS 3.x base score of 9.8, 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-2015-3991 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-3991?: CVE-2015-3991 primarily affects Strongswan. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-3991?: 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-2015-3991 published?: CVE-2015-3991 was published on 2017-09-07 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:strongswan:strongswan:5.2.2:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:5.3.0:*:*:*:*:*:*:*

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Other CWE-19 vulnerabilities

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CVE-2014-4488 — Critical (CVSS 10.0): IOHIDFamily in Apple iOS before 8.1.3, Apple OS X before 10.10.2, and Apple TV before 7.0.3 does not properly validate…
CVE-2014-7247 — Critical (CVSS 10.0): Unspecified vulnerability in JustSystems Ichitaro 2008 through 2011; Ichitaro Government 6, 7, 2008, 2009, and 2010;…
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