Index: wp-includes/wp-db.php
===================================================================
--- wp-includes/wp-db.php	(revision 28630)
+++ wp-includes/wp-db.php	(working copy)
@@ -1367,6 +1367,17 @@
 				}
 			}
 
+			// Set SSL certs if we want to use secure DB connections
+			if ( $client_flags & MYSQLI_CLIENT_SSL ) {
+				$ssl_key = ( defined( 'MYSQL_SSL_KEY' ) && is_file( MYSQL_SSL_KEY ) ) ? MYSQL_SSL_KEY : null;
+				$ssl_cert = ( defined( 'MYSQL_SSL_CERT' ) && is_file( MYSQL_SSL_CERT ) ) ? MYSQL_SSL_CERT : null;
+				$ssl_ca = ( defined( 'MYSQL_SSL_CA' ) && is_file( MYSQL_SSL_CA ) ) ? MYSQL_SSL_CA : null;
+				$ssl_capath = ( defined( 'MYSQL_SSL_CA_PATH' ) && is_dir( MYSQL_SSL_CA_PATH ) ) ? MYSQL_SSL_CA_PATH : null;
+				$ssl_cipher = defined( 'MYSQL_SSL_CIPHER' ) ? MYSQL_SSL_CIPHER : null;
+
+				mysqli_ssl_set( $this->dbh, $ssl_key, $ssl_cert, $ssl_ca, $ssl_capath, $ssl_cipher );
+			}
+
 			if ( WP_DEBUG ) {
 				mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
 			} else {