CVE-2013-6394
Percona XtraBackup before 2.1.6 uses a constant string for the initialization vector (IV), which makes it easier for local users to defeat cryptographic protection mechanisms and conduct plaintext attacks.
Date published : 2013-12-13
http://www.percona.com/doc/percona-xtrabackup/2.1/release-notes/2.1/2.1.6.html