MariaDB Connector/C is a C and C++ client library for connecting applications to MariaDB and MySQL databases. From 3.4.1 until 3.4.10, the MariaDB Connector/C libmariadb Zero-Configuration SSL authentication-switch logic checked certificate trust failure but did not reject a TLS hostname verification mismatch before selecting a non-hashing authentication plugin. An active man-in-the-middle attacker with a valid certificate for another hostname could request mysql_clear_password and obtain the database password inside the attacker-controlled TLS connection. Other MariaDB connectors are not affected. This issue is fixed in version 3.4.10.