Security vulnerability in MySQL and MariaDB
The vulnerability allows an attacker to connect using a known username and any password after repeated connection attempts. A patch is already available for both databases. Affected versions are MariaDB and MySQL versions up to 5.1.61, 5.2.11, 5.3.5, 5.5.22 while, MariaDB versions from 5.1.62, 5.2.12, 5.3.6, 5.5.23 and MySQL versions from 5.1.63, 5.5.24, 5.6.6 are not vulnerable.
Read more here - http://seclists.org/oss-sec/2012/q2/493