Jill Gunter, co-founder of Espresso, has reported a theft of $30,000 in USDC due to a vulnerability in a legacy Thirdweb smart contract. The breach, which occurred on December 9, involved funds being moved through Railgun and was linked to a previously used Thirdweb bridge contract. Thirdweb has confirmed the flaw, which allowed unlimited token approvals, and has since disabled the affected contract. The vulnerability is associated with a 2023 open-source library flaw that has impacted over 500 token contracts and has been exploited at least 25 times, according to ScamSniffer. This incident underscores the persistent security challenges facing decentralized finance (DeFi) infrastructure.