Bitcoin's core developers discovered a vulnerability in its software that would have allowed a miner to insert a “poisoned block” in its blockhchain ...
source https://www.google.com/url?rct=j&sa=t&url=https://boingboing.net/2018/09/19/bitcoins-software-had-a-bug.html&ct=ga&cd=CAIyGmM2Nzk3ODA2ZWViNjVjODI6Y29tOmVuOlVT&usg=AFQjCNG83blTLwmha4IoCvrLPbeMoIxoLg
