A vulnerability in the authentication service of the Cisco Unified Communications Manager IM and Presence (Unified CM IM&P) Service, Cisco TelePresence Video Communication Server (VCS), and Cisco Expressway Series could allow an unauthenticated, remote attacker to cause a service outage for users attempting to authenticate, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient controls for specific memory operations. An attacker could exploit this vulnerability by sending a malformed Extensible Messaging and Presence Protocol (XMPP) authentication request to an affected system. A successful exploit could allow the attacker to cause an unexpected restart of the authentication service, preventing users from successfully authenticating. Exploitation…