BNB Smart Chain paused on Thursday evening after detecting a “potential exploit.”
Binance CEO Changpeng “CZ” Zhao later confirmed the issue on Twitter, saying, “An exploit on a cross-chain bridge, BSC Token Hub, resulted in extra BNB.” The BSC Token Hub impacted is the cross-chain bridge between the BNB Beacon Chain and the BNB Chain, he added.
“The issue is contained now,” CZ wrote. “Your funds are safe.”
“This is an isolated issue on BSC,” a Binance representative told Fortune.
And CZ echoed the same. “The exploit happened with a bridge on the DeFi blockchain. It’s not related to the CEX. The community and teams moved quickly to contain it. That’s pretty much it. All the info is public,” he told Fortune.
CZ also pointed to a Reddit post with more details of the exploit, which noted an initial estimate of funds stolen ranging from $100 million to $110 million, adding that an estimated $7 million had been frozen.
In response to a request for comment, the BSC Hub and BNB Chain teams referred Fortune to the Reddit post cited by CZ.
Cross-chain bridge hacks are extremely common. Case in point: About $2 billion in cryptocurrency has been stolen in cross-chain bridge hacks just this year.
Many on crypto Twitter also pointed this out: “Bridges are the weakness.”
At 2:53 a.m. ET, the BNB Chain team tweeted that the chain is now “running OK.”
Sign up for the Fortune Features email list so you don’t miss our biggest features, exclusive interviews, and investigations.