BleepingComputer reported on 29 October 2026 (US Eastern time) that prediction market platform Polymarket temporarily suspended trading after hackers compromised a third-party service to distribute cryptocurrency-draining JavaScript.

Polymarket said: "One of our third party providers was compromised, and we have referred this to relevant law enforcement," and "Anyone who has been impacted will be made whole," according to BleepingComputer. (source: BleepingComputer)

BleepingComputer says Polymarket placed its exchange into cancel-only mode at 2:05 p.m. ET (2:05 am Perth time on 30 October) and that the incident was marked resolved at 3:05 p.m. ET (3:05 am Perth time on 30 October).

Polymarket's trading account said on X at 3:00 am Perth time on 30 October (19:00 UTC, 29 October): "Trading is now fully back online. We'll make this right and are fully reimbursing all affected traders." (source: Polymarket (@PolymarketTrade) on X) According to BleepingComputer, Hudson Rock researchers identified malicious JavaScript distributed through DebugBear's CDN that was designed to steal cryptocurrency and prediction-market holdings from Polymarket users; BleepingComputer's own analysis found it was designed to hijack authenticated Polymarket trading sessions, liquidate users' prediction-market positions and transfer assets to an attacker-controlled wallet, and that the wallet transferred approximately 28.6 million POL, valued at roughly $2.57 million, to three additional wallets.

BleepingComputer says Polymarket has not disclosed how many users were affected, how much cryptocurrency was stolen, or how the reimbursement process will work. (source: BleepingComputer)

DebugBear, a website performance-monitoring service, said on X at 2:00 am Perth time on 30 October (18:00 UTC, 29 October): "We're impacted by an ongoing security incident. If you use our RUM product, please remove the embed code from your website."

In a later post it said it has engaged specialist cyber incident response support and will work with affected customers directly. (source: DebugBear on X)