Hackers stole $32M worth of Ethereum by abusing Parity wallet flawthehackernews.com
The flaw was in Parity's handling of multi-sig wallets (accounts that operate under the control of multiple people). $75M more was 'stolen' out of vulnerable wallets by the good guys in order to prevent them from being stolen by the bad guys, throwing up quite a bit of controversy. This article dives into the technical details.
And while writing this issue another Ethereum hack came to light, this time of $8.4M during Veritaseum's ICO.