Earlier this year, I – along with some members of our DevOps team – noticed some interesting behavior in libmysqlclient and the MySQL CLI: no matter how hard we tried (no matter how many MYSQL_OPT_SSL_* options we set) we could not make the client enforce the use of SSL. If the server claimed not to support it, the client would happily communicate over plain old, unencrypted TCP!

https://www.duosecurity.com/blog/backronym-mysql-vulnerability