Polymarket Resumes Trading After $2.65M Hack via Third-Party Vendor
The prediction market platform suffered a security breach through a compromised third-party service, resulting in significant user losses.
The prediction market platform suffered a security breach through a compromised third-party service, resulting in significant user losses. This is an original TLT brief synthesising 3 outlets (Crypto Economy, The Cryptonomist, Unchained), with their figures cross-checked, plus live market data, as of Fri, 30 Oct 2026 02:15:02 UTC.
The incident highlights the vulnerability of DeFi platforms to supply chain attacks through third-party integrations, affecting user trust and platform security. It also raises questions about the accountability of platforms in reimbursing users for losses caused by external service providers.
- Attackers stole $2.65M from over 700 Polymarket wallets.
- Compromised third-party monitoring service introduced malicious script.
- Polymarket has committed to reimbursing affected users.
- Platform TVL dropped 4.3% to $354.33M in the past week.
Multiple outlets (Crypto Economy, The Cryptonomist, and Unchained) confirm that Polymarket suffered a security breach on October 29th, resulting in unauthorized withdrawals. Estimates of the stolen amount range from $2.2 million to $2.65 million, with Crypto Economy and Unchained citing the higher figure. The Cryptonomist and Crypto Economy both report that the breach originated from a compromised third-party web performance vendor, DebugBear, which introduced a malicious script into the platform's frontend. Unchained notes that Polymarket has not officially confirmed the exact loss amount, while Crypto Economy states that the platform has activated a 'cancel-only' mode in response.
Polymarket, a decentralized prediction market platform, has resumed trading after suffering a security breach on October 29th that resulted in the theft of approximately $2.65 million from over 700 user wallets. The incident was caused by a compromised third-party web performance vendor, DebugBear, which introduced a malicious script into the platform's frontend.
Users first reported unauthorized withdrawals on social media, prompting Polymarket to restrict trading and activate a 'cancel-only' mode to prevent further losses. The Cryptonomist and Crypto Economy both report that the platform has committed to reimbursing affected users for their losses.
The breach was initially identified through on-chain data and reports from The Block, which indicated that the attackers had drained funds from more than 700 wallets. Estimates of the stolen amount vary, with Crypto Economy and Unchained citing $2.65 million, while other estimates based on blockchain data suggest a range of $2.2 million to $2.65 million.
Polymarket's total value locked (TVL) has dropped by 4.3% over the past week, currently standing at $354.33 million, according to DeFiLlama. This decline reflects the impact of the security breach on user confidence and platform activity.
The broader cryptocurrency market has also experienced a downturn, with the total market cap at $2.65 trillion and 
Bitcoin down 4.86% in the last 24 hours. The Fear & Greed Index currently stands at 30, indicating a state of 'Fear' among investors.
1 key figure independently matched across 3 outlets reporting this story.
TLT extracts the figures each outlet reports and flags the ones that agree. Numbers cited by only one outlet are attributed in the brief, not shown as corroborated.
Figures and sectors in this story, checked live against on-chain aggregators · October 30, 2026.
TLT reads these figures directly from on-chain aggregators (DeFiLlama, mempool.space) at build time — independent of what any outlet reported. Sector totals aggregate every protocol DeFiLlama tracks in that category. Values are live and will change.
Polymarket Resumes Trading After $2.65M Hack via Third-Party — questions & answers
How much was stolen in the Polymarket hack?
Estimates range from $2.2M to $2.65M, with $2.65M being the most cited figure.
What caused the security breach on Polymarket?
The breach was caused by a compromised third-party web performance vendor, DebugBear, which introduced a malicious script into the platform's frontend.
Will affected users be reimbursed?
Yes, Polymarket has committed to reimbursing users for their losses.
Which outlets reported this story?
This is an original TLT brief that synthesises reporting from Crypto Economy, The Cryptonomist, Unchained, with the key figures cross-checked for agreement across them. It is not a copy of any one article — follow the source links above for the original reporting.
Original summary — not financial advice. This is an original TLT brief that summarises a development reported elsewhere and adds live market data for context; it is not the original article and reproduces no part of it. Follow the source link above for full details. Crypto is volatile and high-risk — always do your own research.