Cybercrime $3 Million Reportedly Stolen in Polymarket Hack The decentralized prediction market said hackers targeted some of its users through a compromise of a third-party vendor. By Eduard Kovacs | June 26, 2026 (5:47 AM ET) Flipboard Reddit Whatsapp Whatsapp Email Decentralized prediction market Polymarket has promised to fully refund users affected by a hacker attack that came to light this week. Polymarket is a cryptocurrency-based prediction market platform that enables users to trade on the likely outcomes of real-world events ranging from elections and economic indicators to sports and cultural happenings. The company has shared little information about the incident. “This morning we discovered a 3rd party vendor had been compromised, injecting a malicious script into our frontend for some users. We’ve contained it & removed the affected dependency,” Polymarket said in a Thursday post on X. It noted that impacted users will be contacted and fully refunded, but it did not clarify how many users were affected and how much cryptocurrency was stolen. Blockchain security company PeckShield reported that roughly $3 million worth of pUSD, Polymarket’s USDC-backed trading currency, was stolen via a phishing campaign. Advertisement. Scroll to continue reading. “The attacker bridged the stolen funds from Polygon to Ethereum and swapped them into ~1,893 ETH,” PeckShield said. A blockchain analyst confirmed that the losses total nearly $3 million, with funds stolen from at least 11 victims. It’s unclear who is behind the attack. SecurityWeek has reached out to Polymarket for confirmation of the amount stolen and the number of impacted users. This article will be updated if the company responds. Related : $290 Million Kelp DAO Crypto Heist Blamed on North Korea Related : CryptoBandits Malware Doubles as a Backdoor, Abuses Tor Related : Dozens of Malicious Crypto Apps Land in Apple App Store Related : International Operation Targets Multimillion-Dollar Crypto Theft Schemes Written By Eduard Kovacs Eduard Kovacs (@EduardKovacs) is senior managing editor at SecurityWeek. He worked as a high school IT teacher before starting a career in journalism in 2011. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering. Daily Briefing Newsletter Subscribe to the SecurityWeek Email Briefing for the latest cybersecurity threats, trends, and expert insights. 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