Ostium loses up to $18 million in oracle signer exploit on Arbitrum
Ostium loses nearly $18M in oracle key exploit on Arbitrum Attackers drained nearly $18 million USDC from Ostium after compromising an oracle signer private key, letting them bypass verification checks and submit favorable future prices. Blockaid flagged the incident on July 15, 2026, saying the attacker used a registered PriceUpKeep forwarder and authorized oracle reports to run about 20 looped trades, extracting roughly 32%-35% of the protocol’s ~$34 million TVL.