A vulnerability in the Cisco Discovery Protocol (formerly known as CDP) subsystem of devices running, or based on, Cisco NX-OS Software contain a vulnerability that could allow an unauthenticated, adjacent attacker to create a denial of service (DoS) condition. The vulnerability is due to a failure to properly validate certain fields within a Cisco Discovery Protocol message prior to processing it. An attacker with the ability to submit a Cisco Discovery Protocol message designed to trigger the issue could cause a DoS condition on an affected device while the device restarts. This vulnerability affects Firepower 4100 Series Next-Generation Firewall, Firepower 9300 Security Appliance, MDS 9000 Series Multilayer Director Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Switches, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 3600 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, UCS 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCvc89242, CSCve40943, CSCve40953, CSCve40965, CSCve40970, CSCve40978, CSCve40992, CSCve41000, CSCve41007.
Conclusion & alert: CVE-2018-0331 is rated Moderate Risk (42.3/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.64%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.32% | 0.64% | +0.32% |
| 2 | 2025-11-21 | 0.14% | 0.32% | +0.17% |
| 3 | 2025-11-18 | — | 0.14% | — |
Full EPSS history (7 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.5 | 3.1 | MEDIUM |
|
2.8 | 3.6 | [email protected] |
| 6.1 | 2.0 | MEDIUM |
|
6.5 | 6.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| cisco | nx-os | >= 7.1, < 7.1\(5\)n1\(1\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | >= 7.3, < 7.3\(3\)n1\(1\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | 6.0 | cpe:2.3:o:cisco:nx-os:6.0:*:*:*:*:*:*:* |
| cisco | nx-os | 7.0 | cpe:2.3:o:cisco:nx-os:7.0:*:*:*:*:*:*:* |
| cisco | nx-os | 7.2 | cpe:2.3:o:cisco:nx-os:7.2:*:*:*:*:*:*:* |
| cisco | nx-os | >= 6.2, < 6.2\(20\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | >= 7.2, < 7.2\(2\)d1\(3\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | >= 7.3, < 7.3\(2\)d1\(1\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | >= 8.1, < 8.1\(2\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | >= 8.2, < 8.2\(1\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | 8.0 | cpe:2.3:o:cisco:nx-os:8.0:*:*:*:*:*:*:* |
| cisco | nx-os | < 7.0\(3\)i3 | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | >= 7.0\(3\)i4, < 7.0\(3\)i7\(1\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | < 7.0\(3\)i7\(1\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | >= 6.0, < 7.3\(3\)n1\(1\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | >= 5.2, < 8.1\(1a\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | < 2.2\(8g\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | nx-os | >= 2.5, < 3.1\(2f\) | cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:* |
| cisco | firepower_extensible_operating_system | >= 1.1, < 2.0.1.153 | cpe:2.3:o:cisco:firepower_extensible_operating_system:*:*:*:*:*:*:*:* |
| cisco | firepower_extensible_operating_system | >= 2.1.1, < 2.1.1.86 | cpe:2.3:o:cisco:firepower_extensible_operating_system:*:*:*:*:*:*:*:* |
| cisco | firepower_extensible_operating_system | >= 2.2.1, < 2.2.1.70 | cpe:2.3:o:cisco:firepower_extensible_operating_system:*:*:*:*:*:*:*:* |
| cisco | fxos | >= 2.2.2, < 2.2.2.14 | cpe:2.3:o:cisco:fxos:*:*:*:*:*:*:*:* |
| cisco | fxos | >= 1.1, < 2.0.1.152 | cpe:2.3:o:cisco:fxos:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| http://www.securitytracker.com/id/1041169 | Third Party Advisory VDB Entry |
| https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180620-nxos-cdp | Vendor Advisory |