Polymarket resolves security issue after third-party breach

The prediction market says a compromised vendor caused the problem on its international platform, and it has referred the matter to law enforcement Polymarket says it has fixed a security issue on its international platform. The cause was not its own code but a third-party provider that got compromised. The prediction market has also referred the matter to law enforcement. That step turns an engineering cleanup into a potential criminal case. What happened The research describes this as a supply-chain attack. Malicious code was reportedly injected into the platform’s frontend on or around June 25, 2026. The frontend is the website layer users click through. It sits on top of the smart contracts that actually hold and move funds. That injected code reportedly enabled unauthorized transactions from user wallets. Approximately $2.94 million in pUSD was drained from more than 11 wallets. The attackers then reportedly converted the stolen pUSD into ETH. The swaps came to around 1,893 ETH, according to the research. Polymarket moved to contain the malicious code. It also removed the compromised vendor dependency from its stack. Refunds and what was not touched Affected users are being of...