More Than 400 'Bitcoin Unlimited' Nodes Knocked Offline After Critical Bug Discovered

The number of Bitcoin nodes supporting the Bitcoin Unlimited (BU) scaling framework took a nosedive today after a new exploit was uncovered by Bitcoin Core developers.

According to Peter Todd, a cryptography consultant and contributor to the Bitcoin Core GitHub repo, the newly discovered bug in BU had been present for more than a year:

Several overlooked lines of code in the BU client would allow an attacker to craft a special request to the vulnerable BU client, which would then freeze the client and take it offline.

Since BU nodes only represented less than 13% of all nodes on the Bitcoin network prior to today’s crash, the bug did not endanger the Bitcoin network as a whole. The amount of BU nodes plunged after news of the bug spread within the community.

At press time, charts show that the number of BU nodes plunged on Tuesday under 320.

Bitcoin statistics portal, NodeCounter, which is pro-BU, shows that 305 BU nodes - 5.1% of all Bitcoin nodes - are online at the moment.

Today’s incident is set to ramp up hostilities even further between Bitcoin Core and Bitcoin Unlimited supporters, “If Bitcoin Unlimited was a predominant client, this is a vulnerability that would have left the entire network open to being crashed.,” said one Redditor on the /r/Bitcoin subreddit, which is largely pro-Bitcoin Core.

“Almost one year and no devs in BU noticed this ! Talk about lack of peer review and testing . This is why you cannot "fire" the most competent developers working on core and replace them with amateurs.,” said another Redditor.

The divide between the two camps also ratcheted up yesterday, when one of China’s largest Bitcoin mining pools, Antpool, announced full support for Bitcoin Unlimited. But despite the drama over the past two days, the price of Bitcoin has remained stable around $1250 - only $100 away from its all-time high at $1350.

Network cables photo by Lars P.