A flaw in the most popular software used to verify transactions on the Ethereum network nearly triggered a crisis for the world's most widely used cryptocurrency blockchain.

About half of the Ethereum ecosystem split into a separate chain after a bug in the Go Ethereum, or Geth, software effected users who hadn't implemented an update meant to fix the mistake, said Maddie Kennedy, a spokesperson at the cryptocurrency research firm, Chainalysis.

“This could've been a big problem, but it isn't,” Kennedy said.

About 75% of all users on the Ethereum network utilize Geth as a node to mine the blockchain's native token, Ether, and to create software that runs functions such as decentralized applications.

At its worst, the split — or fork — could have caused a so-called double-spend attack where the same Ether cryptocurrency would have traded twice during any transaction or trade, according to the news site Decrypt. This would've created counterfeit currency and possibly a sharp drop in its value.

Fortunately, most traders using Geth swiftly upgraded their systems, allowing most of the blockchain.to remain on the primary network, instead of pivoting to the forked version, said Kennedy.

While the parallel network still exists, it will eventually disappear as more users of Geth upgrade their systems, she added.

Ether rose for the first time in four trading sessions during New York hours, gaining about 4.6% to $3,272. The second-largest cryptocurrency by market value after Bitcoin has surged more than 300% this year.