Polymarket Halts Trading as Users Report Drained Wallets

Polymarket stopped accepting new trades on October 29, 2026, switching its international platform into cancel-only mode and halting relayer actions while it looks into reports that user wallets were drained and that its frontend may have been compromised, according to Crypto Briefing.

Under the restriction, account holders can withdraw orders they have already placed but cannot submit new ones. Polymarket’s status page recorded the disruption at 18:05 UTC, or 2:05 p.m. Eastern, and classified it as a major outage hitting its Predictions Trading API, the CLOB, crypto.news reported. The platform has described an investigation without confirming a frontend compromise, and it has not issued an official statement on the incident.

Key facts

• Polymarket entered cancel-only mode on Oct. 29, 2026, and paused relayer actions, with Predictions and the Predictions Trading API listed as affected services.
• Users were advised not to connect wallets or sign transactions while the situation develops.
• A trader posting as Car said his account lost $800,000 and that a friend lost $600,000, adding that all his positions had been sold.
• An account named StarPlatinum alleged a recipient wallet grew from $412,000 at 17:25 UTC to $2.68 million at 18:05 UTC, a figure crypto.news reported without official confirmation.
• Polymarket’s international platform runs on Polygon through non-custodial proxy wallets, with trading and settlement in pUSD, a token backed 1:1 by USDC.

Conflicting loss figures, no official confirmation

The accounts of what happened come from social media rather than from Polymarket. Crypto Briefing described reported losses as estimated in the hundreds of thousands, based on user reports that remain unconfirmed. crypto.news carried larger claims: Car’s $800,000 figure and StarPlatinum’s allegation of $2.68 million in withdrawals moving through the platform’s deposit-wallet infrastructure. StarPlatinum also said the suspected recipient accumulated 28.6 million POL and that funds were converted from user deposit balances, while stating that a frontend compromise had not been officially confirmed.

Another user, Jeremy, posted that Polymarket was being hacked and included an image of a wallet message-signing request showing the Polymarket domain, a data field labeled “DepositWallet,” chain ID 137 and an “Unverified” indicator. crypto.news noted the image showed no completed transaction, transaction hash or full verifying-contract field.

The technical distinction carries weight. A frontend compromise means attackers tamper with the website users see, potentially presenting malicious signature prompts that look legitimate, rather than exploiting the on-chain contracts that hold and move funds. Crypto Briefing reported no evidence so far pointing to a core smart-contract exploit, suggesting losses may stem from approvals users were tricked into granting. Freezing relayers — services that submit transactions for users — removes one route for pushing transactions through at scale.

Third security scare of 2026

Polymarket has dealt with at least two earlier incidents this year. In May 2026, an internal POL wallet was breached, with losses estimated between $573,200 and $700,000. In June 2026, a supply-chain attack involving a compromised third-party script drained roughly $3 million in pUSD from fewer than 15 user wallets. Crypto Briefing reported that the platform responded with geographic restrictions and enhanced monitoring of third-party scripts; the fresh reports, again centered on the frontend, raise questions about whether those measures went far enough.

crypto.news reported that Polymarket acknowledged the June vendor compromise, said it had contained the issue and removed the affected dependency, and pledged to reimburse affected customers in full. Blockchain analyst Specter initially put that loss at $2.94 million from at least 11 wallets, and AMLBot later estimated $3.1 million, with funds taken in PUSD on Polygon, converted through Relay, bridged to Ethereum and swapped into ETH. The October 29 notices examined contained no equivalent reimbursement promise.

The two venues should not be confused: Polymarket’s international blockchain platform is separate from its CFTC-licensed US exchange and clearing organization, and the Oct. 29 notice named only the international service’s Predictions Trading API.

Why it matters

Anyone with open positions on Polymarket faces a simple choice — hold, cancel, or wait. The platform does not custody user funds directly, so the exposure is tied to what wallets approved rather than to balances sitting on an exchange. Because Polygon transactions are public, any flows linked to the reported drains can in principle be followed in real time. The episode also lands as a test of confidence for prediction markets more widely; elsewhere, Predict.fun confirmed about 400,000 USDT in unauthorized transfers in an Oct. 27 statement and promised full reimbursement.

What to watch

The next markers are an official statement from Polymarket, confirmation of actual losses, traced fund movements on Polygon, and details on when full trading resumes. Neither the outage notice nor the status posts reviewed set out a reimbursement program, a withdrawal deadline or a timetable for restoring normal trading.

Disclaimer: This article is for information only and is not investment, financial or trading advice. Cryptocurrency prices are highly volatile. Always do your own research.

Sources: Crypto Briefing, crypto.news