Crypto

Polymarket briefly halts international trading after a third-party breach drains user accounts

The prediction market says a compromised third-party provider was to blame and it will fully reimburse affected traders. Trading was back after nearly an hour.

By Jennifer Walsh · Oct 30, 2026, 1:25 AM EDT

Why it matters: At least $2.7 million was withdrawn, per analytics firms, in what Decrypt counts as Polymarket's third incident this year, days before the midterms. It says users will be made whole.

For information only, not investment advice.

Polymarket halted trading on its international platform Thursday after users' accounts were drained. The company said on X that one of its third-party providers was compromised, that it had fixed the issue and referred the matter to law enforcement, and that "Anyone who has been impacted will be made whole." Trading began again at 3 p.m. ET after nearly an hour offline, NBC News reported.

How much is gone is still an estimate. A wallet Arkham identifies as the suspected attacker's holds about $2.65 million in POL, Polygon's native token, Decrypt reported. Two analytics firms told CNBC an account withdrew at least $2.7 million across 710 other wallets. How many users were hit is unclear, per CNBC.

Polymarket didn't name the provider. A person familiar with the matter told CNBC the issue stemmed from a hack of DebugBear, and researchers at Hudson Rock said a script loaded from DebugBear tried to sell logged-in users' positions and transfer the assets. DebugBear said on X it was impacted by an ongoing security incident.

Polymarket's US platform was not compromised, CNBC reported. This is the third incident this year, by Decrypt's count: a roughly $700,000 private-key drain in May and about $3 million stolen via a compromised vendor in June. And it lands days before the Nov. 3 midterms, when both exchanges are expected to see heightened volumes.

Tags: fintech · defi