A vulnerability in Cisco Adaptive Security Device Manager (ASDM) single sign-on (SSO) handler for Cisco Secure FMC Software could allow an unauthenticated, remote attacker to log in as the Cisco ASDM administrator user. This vulnerability is due to improper management of the Cisco ASDM SSO token. An attacker could exploit this vulnerability by performing session token forgery techniques. A successful exploit could allow the attacker to log in as the administrator user and, by repeating this action, keep legitimate administrators locked out of the ASDM indefinitely.