CVE-2020-3172 | Cisco FXOS and NX-OS Software Cisco Discovery Protocol Arbitrary Code Execution and Denial of Service Vulnerability

A vulnerability in the Cisco Discovery Protocol feature of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code as root or cause a denial of service (DoS) condition on an affected device. The vulnerability exists because of insufficiently validated Cisco Discovery Protocol packet headers. An attacker could exploit this vulnerability by sending a crafted Cisco Discovery Protocol packet to a Layer 2-adjacent affected device. A successful exploit could allow the attacker to cause a buffer overflow that could allow the attacker to execute arbitrary code as root or cause a DoS condition on the affected device. Note: Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent). Note: This vulnerability is different from the following Cisco FXOS and NX-OS Software Cisco Discovery Protocol vulnerabilities that Cisco announced on Feb. 5, 2020: Cisco FXOS, IOS XR, and NX-OS Software Cisco Discovery Protocol Denial of Service Vulnerability and Cisco NX-OS Software Cisco Discovery Protocol Remote Code Execution Vulnerability.

Published: 2020-02-26 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-3172 is rated Moderate Risk (60.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.71%). 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-2020-3172

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 2026-05-01 1.08% 0.71% -0.37%
2 2025-11-21 0.43% 1.08% +0.65%
3 2025-11-18 — 0.43% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-3172

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
8.8 3.0 HIGH
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
8.3 2.0 HIGH
AV:A/AC:L/Au:N/C:C/I:C/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:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 6.5 10.0 [email protected]

Weakness enumeration for CVE-2020-3172

Affected software / configurations for CVE-2020-3172

Vendor Product Version Raw CPE
cisco firepower_extensible_operating_system < 2.6.1.187 cpe:2.3:o:cisco:firepower_extensible_operating_system:*:*:*:*:*:*:*:*
cisco firepower_extensible_operating_system >= 2.7, < 2.7.1.106 cpe:2.3:o:cisco:firepower_extensible_operating_system:*:*:*:*:*:*:*:*
cisco ucs_manager < 3.2\(3n\) cpe:2.3:a:cisco:ucs_manager:*:*:*:*:*:*:*:*
cisco ucs_manager >= 4.0, < 4.0\(4g\) cpe:2.3:a:cisco:ucs_manager:*:*:*:*:*:*:*:*
cisco nx-os — cpe:2.3:o:cisco:nx-os:-:*:*:*:*:*:*:*
cisco nx-os 5.2\(1\)sv5\(1.2\) cpe:2.3:o:cisco:nx-os:5.2\(1\)sv5\(1.2\):*:*:*:*:hyper-v:*:*
cisco nx-os 5.2\(1\)sv5\(1.2\) cpe:2.3:o:cisco:nx-os:5.2\(1\)sv5\(1.2\):*:*:*:*:vsphere:*:*
cisco nx-os 7.3\(5\)n1\(1\) cpe:2.3:o:cisco:nx-os:7.3\(5\)n1\(1\):*:*:*:*:*:*:*
cisco nx-os 7.3\(0\)d1\(0.140\) cpe:2.3:o:cisco:nx-os:7.3\(0\)d1\(0.140\):*:*:*:*:*:*:*
cisco nx-os 7.3\(0\)d1\(0.146\) cpe:2.3:o:cisco:nx-os:7.3\(0\)d1\(0.146\):*:*:*:*:*:*:*
cisco nx-os 7.0\(3\)i3\(0.191\) cpe:2.3:o:cisco:nx-os:7.0\(3\)i3\(0.191\):*:*:*:*:*:*:*
cisco nx-os 13.2\(7.230\) cpe:2.3:o:cisco:nx-os:13.2\(7.230\):*:*:*:*:*:*:*
cisco nx-os 14.2\(1i\) cpe:2.3:o:cisco:nx-os:14.2\(1i\):*:*:*:*:*:*:*

References for CVE-2020-3172

cvelogic Threat Intelligence