Woofun AI reports that decentralized perpetual exchange Ostium suffered an oracle attack on Wednesday, resulting in the loss of approximately $18 million in USDC. The attacker utilized compromised oracle signing keys to submit false price reports for future dates, thereby generating fictitious trading profits and extracting funds from the Ostium liquidity vault.

Ostium has identified the vulnerability within its OLP vault and suspended all trading activities while the team conducts an investigation. Deployed on Arbitrum, the protocol facilitates perpetual futures trading for real-world assets such as stocks, commodities, forex markets, and indices. At the time of the incident, the total value locked in the protocol stood at approximately $63 million, meaning the attack drained nearly one-third of the available liquidity. In the first five months of 2026, DeFi protocols have lost over $840 million to exploits, including $292 million from KelpDAO and $285 million from Drift Protocol.