Key Highlights:
- Polymarket confirmed an internal wallet was likely compromised through a private key leak.
- Attackers reportedly drained more than $660,000 from related Polygon addresses.
- The platform said user funds and market resolution systems remain secure.
- The incident adds to previous concerns surrounding Polymarket’s infrastructure and governance systems.
Prediction market platform Polymarket is investigating a potential security incident involving one of its internal wallets on Polygon after attackers reportedly drained more than $660,000 from related addresses.
The issue was first flagged by blockchain investigator ZachXBT, who published details about the suspected exploit through his Telegram channel.
Polymarket Says User Funds Are Safe
Polymarket later acknowledged the incident in a Discord message, stating that the problem appeared to stem from a compromised private key tied to an internal top-up wallet rather than a vulnerability in the platform’s smart contracts or trading infrastructure.
“User funds and market resolution are safe,” the company said.
Josh Stevens, Polymarket’s VP of Engineering for DeFi, also commented publicly, reiterating that the event did not involve a direct contract exploit.
Hundreds of Thousands Reportedly Drained
According to ZachXBT, the suspected attacker targeted wallets connected to Polymarket’s UMA CTF Adapter contract on Polygon.
The adapter helps connect UMA’s Optimistic Oracle with the Gnosis Conditional Tokens framework that powers market resolution on the platform.
Initial reports estimated losses near $520,000, though blockchain analytics firm Lookonchain later placed the total amount drained at more than $660,000.
Security firm PeckShield also confirmed that portions of the stolen funds were transferred to ChangeNOW, a non-custodial crypto exchange.
PolygonScan has since labeled one of the addresses tied to the incident as “Polymarket Adapter Exploiter 1.”
Incident Adds to Ongoing Scrutiny
The security issue comes at a time when Polymarket continues expanding rapidly.
Reports earlier this year suggested the company was exploring a new funding round that could value the platform at roughly $15 billion.
At the same time, Polymarket has faced growing scrutiny surrounding both its governance systems and underlying infrastructure.
In March 2025, a controversial governance incident involving UMA voting allegedly allowed a major prediction market to resolve incorrectly after a single actor controlled roughly 25% of voting power.
Later that same year, Polymarket confirmed some users lost funds following a vulnerability involving a third-party authentication provider.
While the latest incident appears isolated to an internal wallet rather than the protocol itself, it once again highlights the operational security challenges facing large crypto platforms.
