Retailer Overstock mixed up bitcoin and bitcoin cash, letting customers buy items at a steep discount

A serious payment glitch on retail website Overstock.com, which sells everything from furniture to diamond rings, allowed customers to pay with either bitcoin or bitcoin cash interchangeably. It’s a problem because the two cryptocurrencies, which split off from one another last August, have wildly different valuations.

According to CoinMarketCap, one bitcoin is currently worth $13,880, while a single unit of bitcoin cash is valued at $2,355, meaning those who paid with bitcoin cash could buy an item for a fraction of the asking price. Worse still, if a customer paid in bitcoin cash and wanted a refund, Overstock’s system would refund the customer in bitcoin, giving the user more money than they initially paid. It’s not clear how many customers may have taken advantage of this error.

The glitch was first reported by independent journalist Brian Krebs of Krebs On Security. When Krebs purchased solar lights worth $78.27 from the site, Overstock instructed him to send 0.00475574 in bitcoin to their address. Instead of sending bitcoins, Krebs sent 0.00475574 in bitcoin cash, which Overstock accepted. This meant he paid only $12.02 for the lights. He requested a refund, which Overstock gave back in bitcoin worth $77.80 and not bitcoin cash. “A dishonest customer could have used this bug to make ridiculous sums of bitcoin in a very short period of time,” Krebs wrote.

Source: https://www.theverge.com/2018/1/10/16873090/bitcoin-bitcoin-cash-overstock-payment-glitch-cryptocurrency