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Polymarket Resumes Trading After $2.65M Security Breach
· Confirmed
In Short: Polymarket resumed trading operations Thursday after a security breach that affected nearly $2.65 million in user funds.
Crypto Economy reported that Polymarket faced a serious security breach on Thursday, resulting in nearly 1,000 accounts losing $2.6 million. FinanceFeeds noted that the incident exclusively affected Polymarket.com, with institutional operations and regulated divisions remaining unaffected.
Finance Magnates cited Polymarket's statement that the breach stemmed from a compromised third-party real user monitoring (RUM) software provider, DebugBear. FinanceFeeds, however, initially suggested a possible private-key compromise involving an internal operational wallet.
Both outlets agreed that Polymarket's smart contracts deployed on the Polygon network did not suffer from code vulnerabilities.
Crypto Economy and FinanceFeeds reported that Polymarket's engineering team removed the external dependency from its production build via an immediate code deployment.
FinanceFeeds and Crypto Economy stated that Polymarket halted trading on its international platform, Polymarket.com, on October 29, 2026, after a third-party provider was compromised.
FinanceFeeds and Crypto Economy noted that Polymarket initially restricted its exchange to cancel-only mode, allowing customers to withdraw existing orders while new trades stopped processing.
FinanceFeeds and Crypto Economy reported that Polymarket's status page showed the platform allowing order cancellations but blocking new trades.
FinanceFeeds and Crypto Economy agreed that Polymarket pledged to fully reimburse all affected traders.
FinanceFeeds and Crypto Economy reported that Polymarket said it had identified and fixed the issue, referred the incident to UK law enforcement, and would compensate affected users.
FinanceFeeds and Crypto Economy noted that Polymarket's Polymarket Traders account on X confirmed trading was now fully back online.
FinanceFeeds and Crypto Economy reported that Polymarket initially restricted its exchange to cancel-only mode, allowing customers to withdraw existing orders while new trades stopped processing.
FinanceFeeds and Crypto Economy agreed that Polymarket's commitment to reimburse affected users addresses the immediate financial consequences, although the company has not provided a complete public accounting of the losses or a detailed reimbursement timetable.
Background
Polymarket resumed trading operations on Thursday after a security breach that affected nearly $2.65 million in user funds.
What's confirmed
- The company said it had identified and fixed the issue, referred the incident to law enforcement and would compensate affected users.
- Polymarket subsequently said it had identified and fixed the issue, confirmed that one of its third-party providers had been compromised and referred the incident to UK law enforcement.
- Prediction markets platform Polymarket was forced to halt trading on its international platform Thursday for nearly an hour because of what it said was a compromise of third-party software.
- Polymarket pledged to fully reimburse all affected traders. 6 outlets told this the same way.
- Bithumb reported a breach of its internal employee system as South Korean financial firms faced cyberattacks, according to Yonhap News Agency.
- A later update from their Polymarket Traders account confirmed trading was now fully back online.
- Polymarket has suspended new trading on its international platform after a third-party provider suffered a security breach.
- Hackers broke into gambling “prediction market” site Polymarket’s international exchange and stole an undisclosed amount of user funds, CNBC reported on Thursday, with one source telling the network that the incident originated with UK-based web performance monitoring firm and Polymarket vendor DebugBear.
What's still developing
- Polymarket Rocked by Massive Hack as Nearly 1,000 Accounts Lose $2.6 Million Polymarket faced a serious security breach this Thursday on its web interface after a malicious script injected through a third-party vendor compromised user wallets, draining Chainlink Launches Weekend Tokenized Asset Feeds Powered By Perpetual Futures TL;DR Chainlink launched a service that provides reference prices for tokenized assets during weekends and holidays.
- At 18:33 UTC, the company issued a mitigation update guaranteeing that all users who suffered balance losses will receive full financial reimbursement.
- Kalshi reached approximately zkLink Nova Bridge Loses $786K in Forged Root Exploit Blockchain security firm Blockaid detected an ongoing exploit against zkLink Nova’s bridge on Ethereum, reporting that an attacker used a public relayer to inject a Predict.fun Suffers $400K USDT Breach, Promises to Refund Affected Users TL;DR: Predict.fun confirmed unauthorized transfers totaling approximately 400,000 USDT originating from user wallets.
- The script supplied by the third-party vendor contained altered JavaScript code that acted as a wallet drainer by interacting with active sessions on the web interface.
- In another case involving a third-party provider, Pepperstone disclosed a client data breach but said trading accounts, passwords and bank details were unaffected.
- Two firms, Betting Intelligence and Polysights, told CNBC that an account withdrew at least $2.7 million across 710 wallets, while Bubblemaps estimated that about 700 users were affected and about $2.7 million was stolen.
- Blockchain analytics firm Bubblemaps indicated that approximately 700 users were affected by the incident, with an estimated $2.7 million reported as stolen.
- Users alleged unauthorized wallet withdrawals, including a reported $2.68 million in suspicious transfers.
- Until 19:05 UTC, there was a major outage of the Predictions Trading API, also known as CLOB, which was declared resolved.
- Bitget has resumed Bitcoin (BTC) withdrawals after a security breach affecting nearly $388 million.
- ET on October 29, 2026, after it paused activity as a precaution when a third-party provider was compromised, according to Forbes.
- One day earlier, our coverage of the Coinbase Amplitude third-party incident on Oct. 28 showed a vendor problem that exposed contact data while hitting zero funds.