So this was announced by a China security website WooYun (it means Black cloud in Chinese based on sound) earlier on their Weibo, and it is basically telling that there are some shady tweaks that have back-doors is stealing Jailbreak user's iCloud account and password to a remote server, which so far there are roughly 220 thousand accounts has been leaked. They haven't announce that who stole it and what for, but as far as we know that, if they hack into our iCloud accounts, they can have access to our mails, photos or even private stuff.
What can we do now?
I think the best we can do is to delete some shady sources or uninstall some shady tweaks (how can we know? ) or even we change our account password or enable the two step verification.
WooYun's announcement: http://www.wooyun.org/bugs/wooyun-2015-0136806
Weibo post: