Polymarket to Refund Users After Hackers Steal $3 Million via Third-Party Vendor

Hackers exploited a compromised third-party vendor to steal $3 million from Polymarket users. The prediction market says it will fully reimburse affected customers and has contained the breach.

• Hackers injected malicious code into Polymarket's front-end via a compromised third-party vendor, stealing about $3 million in customer funds.
• On-chain investigators at Bubblemaps found fewer than 15 user accounts were affected by the exploit.
• Polymarket said it is refunding impacted customers in full and has removed the malicious code from its website.
• This is Polymarket's second security incident in two months, following a $700,000 employee wallet hack in May.
• Attackers drained pUSD stablecoins from wallets and converted them to ETH, which remains in an Ethereum wallet.

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Last updated 26 Jun 2026