CVE-2018-0331

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.

Published: 2018-06-21 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]

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.

Exploit prediction scoring system (EPSS) score for CVE-2018-0331

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)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-0331

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
2.8 3.6 [email protected]
6.1 2.0 MEDIUM
AV:A/AC:L/Au:N/C:N/I:N/A:C Click to expand
Access vector (AV:A)
Requires access to an adjacent network segment.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:C)
Complete availability impact.
6.5 6.9 [email protected]

Weakness enumeration for CVE-2018-0331

Affected software / configurations for CVE-2018-0331

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:*:*:*:*:*:*:*:*

References for CVE-2018-0331

cvelogic Threat Intelligence