How severe is CVE-2015-4199?

CVE-2015-4199 has a CVSS 2.0 base score of 7.1, rated high severity.

Is CVE-2015-4199 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-4199?

CVE-2015-4199 affects Cisco Ios. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2015-4199?

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

When was CVE-2015-4199 published?

CVE-2015-4199 was published on 2015-06-27 and last updated on 2026-06-17.

CVE-2015-4199

CVE-2015-4199 is a high-severity vulnerability in Cisco Ios with a CVSS 2.0 base score of 7.1. 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-362.

Key facts

Severity: High (CVSS 2.0 base score 7.1)
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-362
Affected product: Cisco Ios
Published: 2015-06-27
Last modified: 2026-06-17

Description

Race condition in the IPv6-to-IPv4 functionality in Cisco IOS 15.3S in the Performance Routing Engine (PRE) module on UBR devices allows remote attackers to cause a denial of service (NULL pointer free and module crash) by triggering intermittent connectivity with many IPv6 CPE devices, aka Bug ID CSCug47366.

Frequently asked questions

What is CVE-2015-4199?: Race condition in the IPv6-to-IPv4 functionality in Cisco IOS 15.3S in the Performance Routing Engine (PRE) module on UBR devices allows remote attackers to cause a denial of service (NULL pointer free and module crash) by triggering intermittent connectivity with many IPv6 CPE devices, aka Bug ID CSCug47366.
How severe is CVE-2015-4199?: CVE-2015-4199 has a CVSS 2.0 base score of 7.1, rated high severity.
Is CVE-2015-4199 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-4199?: CVE-2015-4199 affects Cisco Ios. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2015-4199?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2015-4199 published?: CVE-2015-4199 was published on 2015-06-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:cisco:ios:15.3s:*:*:*:*:*:*:*

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