On October 29, 2026, the prediction market Polymarket transitioned to a cancel-only trading mode and suspended relayer actions. This decision followed unconfirmed reports circulating on social media regarding drained user wallets and a potential compromise of the platform's frontend.
The cancel-only mode allows users to withdraw existing orders but prevents the placement of new ones. Users have been advised to avoid connecting their wallets or signing any transactions until the platform provides an official update on the situation.
While reports suggest losses in the hundreds of thousands of dollars, these figures remain unverified. There is currently no evidence of a vulnerability in the underlying smart contracts on the Polygon network, suggesting the issue may be limited to the website interface.
Polymarket has experienced previous security incidents in 2026. In May, an internal wallet breach resulted in losses estimated between $573,200 and $700,000. In June, a supply-chain attack involving a third-party script led to the loss of approximately $3 million in pUSD tokens.
