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Polymarket halts trading for an hour after third-party provider compromise

Users reported drained wallets on the international site. Polymarket says it is returning $3.9M: $2.7M to 726 drained wallets and $1.19M to about 5,500 wallets for losses during the trading pause. Website monitoring firm DebugBear says it was hit by a security incident the same day.

October 29, 2026 · Effective · Verified 2026-10-31 via official announcement

Polymarket put its international exchange, polymarket.com, into cancel-only mode and paused relayer actions at 14:05 ET on 29 October 2026 while it investigated an incident. It later said one of its third-party providers had been compromised, that it had fixed the issue and referred it to law enforcement, and that anyone impacted will be made whole. Its status page marked the incident resolved at 15:05 ET, and Polymarket then said trading was fully back online and that it is fully reimbursing all affected traders.

In cancel-only mode traders could cancel open orders but could not place new orders, and no trades were processed. The relayer, which submits users' signed transactions such as transfers and redemptions to the blockchain, was paused for the same window.

Polymarket has not named the provider; it later put the number of drained wallets at 726 and the amount taken from them at $2.7 million. Onchain analytics firm Bubblemaps estimated that more than 700 users were affected and that about $2.7 million was converted to POL and moved out; its overall tally of $3.46 million includes $750,000 that one trader says he moved to safety himself, so the stolen total is uncertain. Arkham data cited by The Block and Decrypt shows a wallet linked to the suspected attacker holding about $2.65 million in POL after a series of USDC.e-to-POL swaps. Researchers at Hudson Rock said a script served from DebugBear, a web performance monitoring service, contained wallet-draining code that sent funds to the same address. Polymarket has not confirmed the vendor attribution.

On 30 October at 14:37 UTC Polymarket said 689 of the 726 affected wallets had been refunded in full and that the remaining 37 are being paid as each is verified. It said it will also cover traders who lost money during the trading pause or whose positions were taken, paying $1.19 million to about 5,500 wallets starting that day, for a total of $3.9 million returned: the $2.7 million plus the pause-related losses. It said no claims or tickets are needed, that it removed the compromised provider within the hour, and that it will publish a postmortem; it still has not named the provider.

DebugBear, a website performance monitoring service, said on X at 18:00 UTC on 29 October that it was impacted by an ongoing security incident and asked customers of its real-user monitoring product to remove its embed code from their websites. A person familiar with the matter told CNBC that the Polymarket incident stemmed from the DebugBear hack and that Polymarket referred it to UK law enforcement, where DebugBear is based. CNBC also reported that Polymarket told users on Discord that those who lost less than $10,000 would have funds restored by 30 October, and that those who lost more must sign a release form to be reimbursed; Polymarket's 30 October update says no claims or tickets are needed.

This is the third reported loss of funds at Polymarket in 2026. In May a private key compromise drained about $700,000 from an internal top-up wallet, and in June a compromised third-party vendor injected malicious code into the website and took about $3 million from fewer than 15 accounts, which Polymarket said it would refund in full. The incident was reported on the international platform; Polymarket did not report any impact on Polymarket US.

“In total, we’re returning $3.9M to traders: the $2.7M plus $1.19M to cover pause-related losses.”

— Polymarket Traders on X

Who this affects

Users of the international polymarket.com site, especially those whose wallets were drained; anyone with open orders or pending transfers during the halt.

Polymarket at a glance

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