Ostium suffered an oracle attack, resulting in the loss of 18 million USDC, with about one-third of its liquidity drained.

Odaily reported that the decentralized perpetual contract exchange Ostium was attacked via an oracle exploit on Wednesday, resulting in a loss of approximately 18 million USDC. The attacker submitted false price reports for future dates using compromised oracle signature keys, generating fraudulent trading profits and receiving payouts from the Ostium liquidity vault.

Ostium stated that it has identified issues with the OLP vault and has suspended all trading. The team is currently investigating. Ostium is deployed on Arbitrum and offers perpetual futures trading related to real-world assets such as stocks, commodities, foreign exchange markets, and indices.

At the time of the attack, the Ostium protocol had a total value locked of about $63 million, and the incident depleted nearly one-third of its liquidity. In the first five months of 2026, DeFi protocols lost over $840 million to theft, including $292 million from KelpDAO and $285 million from Drift Protocol.