Polymarket Pauses Trading After $2.65 Million Exploit

Update (Oct 29, 19:12 UTC): Polymarket placed its exchange in cancel-only mode following an exploit that resulted in over $2.5 million in losses within minutes. The platform stated that a third-party provider was compromised in the incident.

Prediction market platform Polymarket restricted trading to cancel-only mode and paused relayer actions on Oct. 29 while investigating a major outage affecting its Predictions Trading API, known as the CLOB. According to CryptoNews, users reported unauthorized wallet withdrawals during the disruption.

Incident Details and Status

Polymarket’s incident notice recorded the disruption at 18:05 UTC, noting that the exchange entered cancel-only mode where users could cancel existing orders, but new orders and trades failed to process. Relayer actions remained paused during the investigation.

Trader accounts on social media reported significant individual losses. A trader named Car stated his account was drained of $800,000 and claimed a friend lost $600,000, suspecting a frontend compromise. Another account, StarPlatinum, alleged that hundreds of withdrawals passed through Polymarket’s deposit-wallet infrastructure over roughly an hour, accumulating up to $2.68 million. Polymarket’s examined statements have not officially confirmed the individual losses, aggregate amounts, or the exact attack method.

## Key facts

• Polymarket restricted trading to cancel-only mode and paused relayer actions on Oct. 29.
• The disruption began at 18:05 UTC and affected the Predictions Trading API.
• Traders reported unauthorized withdrawals and suspected a frontend compromise.
• Social media accounts alleged losses ranging from $800,000 up to $2.68 million, though unconfirmed by the platform.