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Vulnerabilities

Vulnerability · CVE-2016-1409

Cisco IOS Improper Input Validation

Published May 26, 2016 · catalog updated May 26, 2016 · Cisco IOS

Patch now

CVE-2016-1409 is in the CISA known-exploited catalog. Confirm Cisco IOS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Unknown—
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
3.90%
Remediation
Remediation guidance
Affected products
vendor Cisco IOS

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Cisco IOSversion unspecified

How to fix CVE-2016-1409

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2016-1409 is in the CISA known-exploited catalog. Confirm Cisco IOS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

No weakness class is stored. EPSS 3.90%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Cisco security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. May 26, 2016 · VulnCheck KEV

    Detected

    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.

  2. May 26, 2016 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Sources

  • CVE.orgVulnerability recordCVE-2016-1409

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2016-1409

    30-day exploitation probability 3.9%

    first.org
  • VulnCheck KEVConfirmed exploitationCVE-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 exploi

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.