Open Access Management (OpenAM) is an access management solution. Prior to 16.1.1, MSISDNValidation in the MSISDN authentication module concatenates the request-supplied MSISDN value into an LDAP search filter without escaping, while the default empty trusted-gateway list allows all traffic. In a realm where an MSISDN module is enabled in a reachable authentication chain, an unauthenticated remote attacker can inject LDAP filter metacharacters, select an arbitrary matching user, and obtain a normal authenticated OpenAM session without a password. This issue is fixed in version 16.1.1.