Unspecified vulnerability in Oracle MySQL 5.7.12 and earlier allows remote administrators to affect availability via vectors related to Server: Optimizer.
http://www.ubuntu.com/usn/USN-3040-1
http://www.securitytracker.com/id/1036362
http://www.securityfocus.com/bid/91976
http://www.securityfocus.com/bid/91787
http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html