Unspecified vulnerability in Oracle MySQL 5.1.67 and earlier, 5.5.29 and earlier, and 5.6.10 and earlier allows remote authenticated users to affect availability via unknown vectors related to Server Locking.
http://www.oracle.com/technetwork/topics/security/cpuapr2013-1899555.html
http://security.gentoo.org/glsa/glsa-201308-06.xml