pgjdbc, the PostgreSQL JDBC Driver, versions 42.7.11 through 42.7.13 enforce no restriction when the requireAuth connection property excludes all six authentication methods the driver knows, for example requireAuth=!password,!md5,!gss,!sspi,!scram-sha-256,!none. The driver then accepts any method the server asks for, including cleartext password authentication. A value without a method in it, such as requireAuth=, (a single comma), is affected the same way. An attacker positioned between the application and its server can ask for cleartext password authentication and receive the database password. A positive list such as requireAuth=scram-sha-256, and a partial exclusion such as requireAuth=!password,!md5, are enforced correctly. The property has no default value, so a deployment that does not set it is not affected. 42.7.14 fixes the problem: such a connection is refused with SQLState 08004, and a value without a method in it is rejected as invalid.