CVE-2024-20294: Cisco Firepower Extensible Operating System

Medium severity, CVSS 6.6. EPSS: 0.3% chance of exploitation in the next 30 days.

A vulnerability in the Link Layer Discovery Protocol (LLDP) feature of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of specific fields in an LLDP frame. An attacker could exploit this vulnerability by sending a crafted LLDP packet to an interface of an affected device and having an authenticated user retrieve LLDP statistics from the affected device through CLI show commands or Simple Network Management Protocol (SNMP) requests. A successful exploit could allow the attacker to cause the LLDP service to crash and stop running on the affected device. In certain situations, the LLDP crash may result in a reload of the affected device. Note: LLDP is a Layer 2 link protocol. To exploit this vulnerability, an attacker would need to be directly connected to an interface of an affected device, either physically or logically (for example, through a Layer 2 Tunnel configured to transport the LLDP protocol).

Affected products

• Cisco Firepower Extensible Operating System: version 2.2.1.63 only; version 2.2.1.66 only; version 2.2.1.70 only; version 2.2.2.17 only; version 2.2.2.19 only; version 2.2.2.24 only; …
• Cisco NX-OS: version 12.0(1m) only; version 12.0(1n) only; version 12.0(1o) only; version 12.0(1p) only; version 12.0(1q) only; version 12.0(1r) only; …
• Cisco Unified Computing System: version 3.1(1e) only; version 3.1(1g) only; version 3.1(1h) only; version 3.1(1k) only; version 3.1(1l) only; version 3.1(2b) only; …

Published 2024-02-29. Last modified 2026-06-17.