Two forks that make weak ethereum, and this is sad. Hardfork itself has been postponed for reasons of vulnerability to accounts in exchange, so we will wait for hardfork to return which has good development later.
On 15th of Jan, 2019 at 12.08 PM PT exactly, the Ethereum core developers and security community decided to postpone the planned Ethereum Constantinople hard fork that would have ideally occurred on 16th January, 2019 at block 7,080,000. There were certain issues identified by ChainSecurity and TrailOfBits wherein some smart contracts could utilize the code patterns that can make them vulnerable to a reentrancy attack. The attacker might get the entire right of the transaction, i.e, can totally decide on the treasury splitting service wherein he can create a pair with the first address being the contract and the second is any attacker account. In brief, he will get the leverage to steal other people's ether and can continue doing so. He can have both the transfer and send authority following by a state changing operation.
Complete details of Constantinople Hard Fork Delayed: https://coinswitch.co/news/ethereum-hard-fork-jan-19-know-everything-about-3-upcoming-eth-hard-forks