Technology

Polymarket briefly halts trading after third-party compromise; theft reports unconfirmed

Polymarket says it will reimburse affected traders while user losses and theft totals remain unconfirmed.

Updated Oct 29, 2026 · 20:34 UTC2 reports

The short version

Polymarket briefly halted trading on its international platform Thursday after a compromise of third-party software.[NBC News]
Unconfirmed user reports describe drained wallets, and The Block reported about $2.65 million was siphoned, citing Arkham data.[NBC News]
Polymarket says it will fully reimburse affected traders and has referred the attack to British law enforcement.[NBC News]
Total losses and affected user counts remain unconfirmed, as Bubblemaps estimated about 700 users and $2.7 million stolen.[Wired · NBC News]

Polymarket halted trading on its international platform for nearly an hour on Thursday after a compromise of third-party software.[NBC News]
DebugBear said on X that it was experiencing an ongoing security incident around 2 p.m. ET Thursday.[NBC News]
The Block reported that about $2.65 million in cryptocurrency was siphoned from user wallets, citing Arkham data.[NBC News]
Bubblemaps reported that about 700 users appear affected, with approximately $2.7 million stolen.[Wired]
Polymarket said it is fully reimbursing affected traders and has referred the matter to British law enforcement.[NBC News]

Polymarket has not confirmed that users lost money, and a representative declined to comment on the reported theft figure or the precise nature of the attack.[NBC News]
Reported theft totals differ between $2.65 million from The Block, citing Arkham, and $2.7 million from Bubblemaps; the affected-user count is an estimate.[Wired · NBC News]
An anonymous person familiar with the details said attackers reached funds through DebugBear software; this account is not independently confirmed in the reporting.[NBC News]

Outlet counts describe coverage, not independent confirmation. Reports may share a wire service or original source.