How severe is CVE-2016-1409?

CVE-2016-1409 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2016-1409 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-1409?

CVE-2016-1409 primarily affects Cisco Ios. In total, 4891 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-1409?

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-2016-1409 published?

CVE-2016-1409 was published on 2016-05-29 and last updated on 2026-06-17.

CVE-2016-1409

CVE-2016-1409 is a high-severity vulnerability in Cisco Ios with a CVSS 3.x base score of 7.5. 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-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Cisco Ios
Published: 2016-05-29
Last modified: 2026-06-17

Description

The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in Cisco IOS XE 2.1 through 3.17S, IOS XR 2.0.0 through 5.3.2, and NX-OS allows remote attackers to cause a denial of service (packet-processing outage) via crafted ND messages, aka Bug ID CSCuz66542, as exploited in the wild in May 2016.

Frequently asked questions

What is CVE-2016-1409?: The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in Cisco IOS XE 2.1 through 3.17S, IOS XR 2.0.0 through 5.3.2, and NX-OS allows remote attackers to cause a denial of service (packet-processing outage) via crafted ND messages, aka Bug ID CSCuz66542, as exploited in the wild in May 2016.
How severe is CVE-2016-1409?: CVE-2016-1409 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2016-1409 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-1409?: CVE-2016-1409 primarily affects Cisco Ios. In total, 4891 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-1409?: 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-2016-1409 published?: CVE-2016-1409 was published on 2016-05-29 and last updated on 2026-06-17.

References

Affected products (4891)

cpe:2.3:o:cisco:ios:12.0\(1\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)db:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)s:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)t:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)t1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xa:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xa1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xa2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xa3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xa4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xb:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xb1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xe:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1a\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)db:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)s:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)t:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)t1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xc:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xc1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xc2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xd:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xd1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xe:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xe1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xe2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xe3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xe4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xf:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xf1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xf2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xh:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xh1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2a\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2a\)t1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2b\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(3\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(3\)db:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(3\)dc:*:*:*:*:*:*:*

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