Polymarket Halts International Trading Following Third-Party Security Breach
Prediction market platform Polymarket temporarily paused trading on its international exchange on Thursday following a security incident that compromised a third-party service provider, the company announced. Trading was suspended for about an hour before resuming at 3 p.m.
Third-Party Software Vulnerability Affects User Wallets
The disruption stemmed from an external breach rather than a vulnerability in Polymarket’s core infrastructure. Reports from blockchain analytics firms and industry outlets linked the source of the incident to DebugBear, a United Kingdom-based company that provides website performance-monitoring tools. DebugBear’s own website became unavailable on Thursday afternoon, and the firm posted on X that it was impacted by an ongoing security incident while advising clients to remove its embed code from their websites.
During the brief shutdown, users on Polymarket’s Discord channel reported seeing unauthorized withdrawals from their accounts. According to an analysis of publicly available data provided to CNBC by analytics firms Betting Intelligence and Polysights, a single account on the platform withdrew at least $2.7 million across 710 separate wallets. Dan Zimmermann, chief intelligence officer at Betting Intelligence, described the event to CNBC as a significant and new form of breach for the platform.
We're impacted by an ongoing security incident.If you use our RUM product, please remove the embed code from your website.
Response, Restitution, and Law Enforcement Involvment
Following the detection of unauthorized transactions, Polymarket halted trading on its international domain out of an abundance of caution while engineering teams secured the platform. The company stated that the issue has been fixed on its end. Polymarket confirmed that it has referred the incident to law enforcement authorities in the United Kingdom, where DebugBear is based.
Regarding user reimbursement, Polymarket communicated in its community chatrooms that users who had less than $10,000 stolen from their wallets will receive restored funds by October 30. Individuals with losses exceeding $10,000 must sign a formal release form to receive their reimbursements. The platform’s separate U.S.-regulated exchange, Polymarket US, remained fully operational and was not compromised by the breach.
🟡 Polymarket.com: A fix is out and we're keeping an eye on it. Trading will resume at approximately 3pm ET.
Prior Security Incidents and Market Valuation Context
The Thursday security breach marks the second time in recent months that Polymarket traders have faced financial losses due to third-party vendor compromises. In June 2026, a similar vendor breach resulted in more than $2 million in losses for impacted users, according to reporting by WIRED. Despite these technical setbacks, the prediction market has experienced substantial financial growth, closing a $1 billion fundraising round in August 2026 led by 1789 Capital, which brought the company’s valuation to $21 billion.
Platform Preparations Ahead of Upcoming U.S. Midterm Elections
The temporary trading halt occurred just days before both Polymarket’s international and U.S. platforms anticipated trading volumes surrounding the U.S. midterm elections on November 3.
Frequently Asked Questions About the Polymarket Security Incident
How many Polymarket users were ultimately affected by the breach?
Polymarket has not officially released a precise headcount of impacted traders. However, blockchain analysis groups including Bubblemaps and Arkham estimated that approximately 700 user wallets experienced unauthorized outflows during the incident.
Were traders using the regulated U.S. platform impacted?
No. Polymarket confirmed that its U.S.-based exchange operated normally and remained entirely separate from the infrastructure compromise that affected the international platform.
We've identified & fixed an issue impacting our international platform, Polymarket.com. One of our 3rd party providers was compromised, and we have referred this to relevant law enforcement.Anyone who has been impacted will be made whole.Out of an abundance of caution, we…
What specific timeline did Polymarket set for issuing user refunds?
In communications with traders on Discord, the platform announced that users who lost less than $10,000 will receive their restored funds by October 30, while users with losses greater than $10,000 are required to sign a release form to process their repayments.
More on Polymarket
Trading is now fully back online.We’ll make this right and are fully reimbursing all affected traders.
🚨 UPDATE: Polymarket says it has fixed an issue involving a compromised third-party provider and will make affected users whole, with trading temporarily halted as it works to restore the platform.
Hackers Swipe Millions From Polymarket Users in Latest Security BreachTraders who lost money on the incident will be ‘made whole,’ the prediction-markets platform said https://t.co/wK3p4ezQ1j
🚨 JUST TODAY:• Polymarket: $2.7M reportedly stolen.• Binance: $5.7B reportedly drained in suspected hack. pic.twitter.com/kRtrS59jff