Cisco FXOS and NX-OS Software Link Layer Discovery Protocol Denial of Service Vulnerability

Cisco Security Advisory

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).

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:

This advisory is part of the February 2024 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: February 2024 Semiannual Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Security Impact Rating: Medium

CVE: CVE-2024-20294