Javamail does not properly handle a series of invalid login attempts in which the same e-mail address is entered as username and password, and the domain portion of this address yields a Java UnknownHostException error, which allows remote attackers to cause a denial of service (connection pool exhaustion) via a large number of requests, resulting in a SQLNestedException. NOTE: Sun disputes this issue, stating "The report makes references to source code and files that do not exist in the mentioned products.