Bitcoin tumbled more than 10 percent over the weekend to its lowest in two months, after a relatively small South Korean exchange said it was hacked.

Over the weekend, crypto exchange Coinrail tweeted that it was hacked, and noted that lesser-known cryptocurrencies such as Pundi X were among those affected, according to Google Translate. The Pundi X-bitcoin pair is the most-traded on Coinrail, CoinMarketCap data showed.

However, Coinrail's public statements did not mention bitcoin, according to Google Translate.

Nevertheless, Bitcoin hit a low of $6,647.33 on Sunday, its lowest since April 9, according to CoinDesk's bitcoin price index, and coincided with a broader crypto sell-off. The digital currency traded off those lows Monday afternoon, near $6,700.