Apple has fixed an iCloud Keychain vulnerability that could have been exploited by hackers to steal sensitive data from iCloud users. The flaw allowed hackers to run man-in-the-middle (MitM) attacks to obtain sensitive user information (i.e. names, passwords, credit card data, and Wi-Fi network information) Apple promptly fixed the issue, along with other bugs in its products, at the end of March. Apple implemented end-to-end encryption for the sync process, the encryption relies on a syncing identity key.”]
Source: http://securityaffairs.co/wordpress/58948/hacking/icloud-keychain-vulnerability.html