BREAKING: Polymarket Users Lose Over $2M With Third-Party Partner Compromised

Crypto predictions platform Polymarket halted trading on its international platform as one of its third-party partners was compromised.

Already, several Polymarket users have reported losses. One user reported losing $800,000, and their friend parted with $600,000. The bright side? The prediction platform promised to make these affected users whole.

Despite acknowledging the issue, Polymarket did not disclose the identity of the compromised partner.

We’ve identified & fixed an issue impacting our international platform, Polymarket⁠.com. One of our 3rd party providers was compromised, and we have referred this to relevant law enforcement.

Anyone who has been impacted will be made whole.

Out of an abundance of caution, we have temporarily halted trading & are working to bring the platform back online.

— Polymarket Traders (@PolymarketTrade) October 29, 2026

Polymarket Under Heat!

Although the cause of the attack remains unconfirmed, some users suspect that it was a front-end attack. Several users reported seeing unauthorized fund transfers.

On-chain data from Arkham reveals that the attacker’s address has received 28.6 million POL tokens worth $2.68 million as of this writing.

Individuals familiar with the matter have pinpointed DebugBear, a UK-based website monitoring platform, as the third-party vendor that was compromised. An accompanying X post from the platform acknowledging the security issue endorses this claim.

We’re impacted by an ongoing security incident.

If you use our RUM product, please remove the embed code from your website.

— DebugBear (@DebugBear) October 29, 2026

To reduce casualties, Polymarket set its system to cancel-only mode. This means that traders can only cancel existing open orders and cannot open new positions. It has also paused relayer actions, making it impossible for transactions to be validated or submitted on the blockchain.

An hour after halting operations, the prediction marketplace resumed activities. It stated via its Status page that the issue has been resolved. It added that it has already commenced reimbursing affected users.

Not the First

The latest incident is especially disturbing because Polymarket has previously suffered a front-end exploit. In late June, 11 wallets using the prediction marketplace reported losses of nearly $3 million. The issue stemmed from a breach at Polymarket’s third-party vendor.

Since Polymarket did not reveal the identity of the third-party partner at the time, it remains unclear whether it is DebugBear that got hacked again in June.

Undoubtedly, incidents like these could further make it difficult for Polymarket to expand its operations in some countries. Already, some nations like Argentina and Portugal have blocked the platform from operating locally.