MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases. From 3.0.0 until 3.3.7 and 3.4.5, during caching_sha2_password authentication, the authentication-more-data response was treated as a length-encoded byte array, memory was allocated from the server-declared length, and authResult[0] was accessed without ensuring a byte existed. A malicious or compromised server, or a machine-in-the-middle attacker, could declare a very large length or send an empty response before any password was transmitted. The malformed packet could cause excessive allocation or an unchecked ArrayIndexOutOfBoundsException escaping from DriverManager.getConnection(). This issue is fixed in versions 3.3.7 and 3.4.5.