Poloniex should suspend the trading of ByteCoin until it can be determined whether or not the bug has been exploited, as some reports indicate:

https://www.reddit.com/r/Monero/comments/6buu5j/disclosure_o...

It's surprising that an exchange like Poloniex would allow trading in potentially fradulent ByteCoins to continue.

https://poloniex.com/exchange#btc_bcn

However, in Poloniex's defense, they could argue that the security disclosure just 24 hours ago has not given them enough time to respond, and that up until now they were only ever aware of a (fake) DoS bug impacting CryptoNote coins, rather than a critical vulnerability.

https://getmonero.org/2017/05/17/disclosure-of-a-major-bug-i...

2017-02-21: The patch is surreptitiously snuck into the Monero codebase in pull request #1744. It is kept secret to prevent it being used to attack other CryptoNote coins.

2017-02-22: A point release of Monero is rushed out so that exchanges and mining pools can update, under the guise of it preventing a RingCT DoS attack (such attack did not exist, but it seemed a fair explanation).