#Bitcoin core code update

This could, in a worst-case scenario, crash the entire network or fracture it so that clusters of nodes are split off from each other. Roughly 95 percent of users running Bitcoin nodes use Core, and the now-fixed bug meant that any Core node receiving the poisoned block would have been instantly killed instead of simply rejecting it for being invalid. This poisoned block could then be sent around the Bitcoin network, crashing the software of any user that receives it.īitcoin is a peer-to-peer network that works thanks to a network of “nodes” all making sure that transactions conform to the blockchain’s rules (for example, that you can’t spend the same coins twice). The vulnerability essentially allowed miners-the people who run computers 24/7 to guess a number that adds a block of Bitcoin transactions to the blockchain for a reward-to create a kind of poisoned block by including a transaction that attempts to spend the same coins twice.

#Bitcoin core code update

Some cryptocurrencies built using Bitcoin Core’s code were also affected-for example, Litecoin patched the same vulnerability on Tuesday.ĭocumentation describes the bug as a “denial-of-service vulnerability” that was introduced into Bitcoin Core in an update last year. Notably, the bug was not in the Bitcoin protocol itself but in its most popular software implementation.

There are many motivated people like this, and they could have brought the network down.” “That is less money than what a lot of entities would pay for a 0-day attack on many systems. “For less than $80,000, you could have brought down the entire network,” Emin Gün Sirer, an associate professor of computer science at Cornell University told me over the phone.