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

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-02-26 · updated 2026-06-17
Weakness: CWE-20

Description

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.

Affected products

Cisco Firepower Extensible Operating System (FXOS): before 2.6.1.187; from 2.7 before 2.7.1.106 — fixed in 2.6.1.187, 2.7.1.106
Cisco NX-OS: 5.2(1)sv5(1.2), 7.3(5)n1(1), 7.3(0)d1(0.140), 7.3(0)d1(0.146), 7.0(3)i3(0.191), 13.2(7.230) (+1)
Cisco Ucs Manager: before 3.2\(3n\); from 4.0 before 4.0\(4g\) — fixed in 3.2\(3n\), 4.0\(4g\)

How to fix

Upgrade to a fixed version: Cisco Firepower Extensible Operating System (FXOS) 2.6.1.187, 2.7.1.106; Cisco Ucs Manager 3.2\(3n\), 4.0\(4g\). Check the vendor advisory for mitigations.

References

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