The Polymarket Midterms 2026 website installed on a laptop in Forest Hills, New York, USA, Wednesday, October 28, 2026.
Gabby Jones | Bloomberg | Getty Images
Some users of prediction market platform Polymarket have had funds stolen from their accounts due to a hack by an anonymous third-party provider.
Polymarket has contacted law enforcement and has agreed to reimburse any affected merchants. It is unclear how many users were affected. The company’s US platform was not compromised.
Traders first reported on social media platforms that they were seeing unauthorized withdrawals from their accounts on Thursday afternoon. In response, the company halted operations on its international platform.
Polymarket said it resolved the issue on its end and trading resumed at 3:00 p.m. ET.
A person familiar with the matter told CNBC that they reported the problem stemmed from a hack of DebugBear, a website performance monitoring platform. DebugBear in an article on X said it was hit by a security incident on Thursday. The person close to the Polymarket outage said the company referred the matter to UK law enforcement, as that’s where DebugBear is based.
DebugBear did not immediately respond to a request for comment.
Polymarket International Prediction Exchange operates as a decentralized finance platform on the Polygon blockchain and is not regulated in the United States.
The disruption comes just days before the company’s international and U.S. exchanges are expected to see increased volumes during the U.S. midterm elections on November 3.
In June, a similar incident occurred when Polymarket said a third-party vendor had been “compromised” and that the company would refund affected users.
Disclosure: CNBC and Kalshi have a business relationship that includes customer acquisition and minority investment.
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