It's a number that's bound to raise some eyebrows: 220,000 iCloud accounts breached in what is being called a backdoor attack made possible by a malicious jailbreak tweak.
This leak, which was brought to our attention by /r/jailbreak, was reported by a Chinese online vulnerability reporting platform called WooYun. It's an information security platform where security researchers report vulnerabilities and vendors give feedback. WooYun is a legit site, and it has reported thousands of security related issues in this month alone.
On a post on its website, WooYun details the nature of this particular attack, stating that 220,000 accounts have been compromised as a result of a malicious jailbreak tweak or plug-in. It also states that WooYun has notified vendors—presumably Apple—and are awaiting processing.
It's sure to make any jailbroken iPhone user take note, but before you get too alarmed, understand that this hack has nothing to do with Apple's security, and that there appears to be special circumstances in the case of this breach.