The decentralized finance (DeFi) protocol SenecaUSD was exploited due to a critical approval exploit involving an open external call vulnerability, leading to the loss of over 1,900 $ETH, valued at approximately $6.5M. The exploit allowed attackers to transfer funds from users who had approved transactions with the protocol, resulting in a $3m+ loss across eth/arb and a dramatic 65% drop in the value of its native $SEN token. Security teams from SlowMist, PeckShield, and others quickly issued alerts, advising users to revoke their approvals for specific addresses to prevent further losses. The Seneca Protocol team confirmed that 80% of the stolen funds were returned following a whitehat request, resulting in the recovery of approximately $5.3 million in ETH. The incident has raised concerns over the security of Ethereum's token approval mechanism and the safety of assets held in users' wallets within DeFi platforms.