A vulnerability in the Extensible Messaging and Presence Protocol (XMPP) service of the Cisco Meeting Server (CMS) before 2.0.6 and Acano Server before 1.8.18 and 1.9.x before 1.9.6 could allow an unauthenticated, remote attacker to masquerade as a legitimate user. This vulnerability is due to the XMPP service incorrectly processing a deprecated authentication scheme. A successful exploit could allow an attacker to access the system as another user.