Anthropic's Claude Mythos AI Finds DeFi Bugs: Approvals at Risk

Anthropic released its Claude Mythos model, and internal tests show it can find critical flaws in smart contracts. The company's cybersecurity team said automated agents powered by this model detected vulnerabilities in contracts holding millions of dollars in cumulative value.

That changes the risk calculus for anyone with active token approvals on DeFi protocols. The discovery cost for attackers just dropped. The window to clean up approvals just got narrower.

Claude Mythos Detection: Smart Contract Vulnerabilities Found in Minutes

Claude Mythos is a large language model fine-tuned for code analysis. Anthropic ran automated agents against a set of live smart contracts and found exploitable weaknesses. The company did not name the specific protocols. The implication is broad: any contract with a known or unknown vulnerability is now easier to find.

For DeFi users, the direct risk is wallet approvals granted to protocols that may have undiscovered flaws. A compromised contract can drain approved tokens without further user action. The standard advice: revoke approvals on unused or older contracts. That advice becomes urgent when attackers can deploy AI-driven scans.

Why the Detection Speed Matters

Smart contract audits take weeks. Claude Mythos can scan code in minutes. Anthropic's test focused on automated agents. These agents can interact with blockchain data and execute transactions. A human hacker needs time to read code and craft an exploit. An AI agent can iterate faster.

That speed cuts both ways. Developers can use it to find bugs before deployment. Attackers can use it to find bugs before developers patch. Many DeFi protocols use proxy and upgradeability patterns that are notoriously difficult to audit. The first successful exploit using AI-assisted vulnerability detection will reset market expectations for DeFi security.