An ARP flood attack, in which overwhelming number of ARP requests are sent, could result in broadcast ARP responses, which in turn could render the network vulnerable to conversation eavesdropping. Corruption of the ARP cache could result in traffic rerouting to intercept voice and data traffic.
NIST recommendation
Use authentication mechanisms provided wherever possible and limit physical access to the VoIP network segment.
How Messaging addresses the vulnerability
For more information, see Security strategies to combat ARP spoofing.