The "iCloud Find My Mac" feature in Apple OS X before 10.10 does not properly enforce rate limiting of lost-mode PIN entry, which makes it easier for physically proximate attackers to obtain access via a brute-force attack involving a series of reboots.
http://archives.neohapsis.com/archives/bugtraq/2014-10/0101.html
https://exchange.xforce.ibmcloud.com/vulnerabilities/97636