Same problem here! I’m just disabling Wordfence and building a more-hardened .htaccess because it’s filling up the log mount point with mysql binary logs enabled.
$wp_version = '3.9';
$wp_db_version = 27916;
Apache/2.4.7
mysqld --version
mysqld Ver 5.5.37-MariaDB-1~saucy-log for debian-linux-gnu on x86_64 (mariadb.org binary distribution)
php --version
PHP 5.5.9-1ubuntu4 (cli) (built: Apr 9 2014 17:11:57)
Copyright (c) 1997-2014 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2014 Zend Technologies
with XCache v3.1.0, Copyright (c) 2005-2013, by mOo
with Zend OPcache v7.0.3, Copyright (c) 1999-2014, by Zend Technologies
with XCache Optimizer v3.1.0, Copyright (c) 2005-2013, by mOo
with XCache Cacher v3.1.0, Copyright (c) 2005-2013, by mOo
with XCache Coverager v3.1.0, Copyright (c) 2005-2013, by mOo
Bumping for bugfix!