Anthropic has publicly released Fable 5, an advanced model from its Claude Mythos series, equipped with security features for general use. Designed to manage risk, Fable 5 redirects sensitive cybersecurity inquiries to other models, like Claude Opus 4.8, to ensure safety. However, in the context of decentralized finance (DeFi), this release has sparked concerns over potential security threats within the cryptocurrency community.
What Worries Are Arising in the Crypto World?
Last month’s revelations showed that the Mythos model could identify thousands of significant vulnerabilities in essential software. This ability has led to a debate on the wisdom of making such a tool public. Anthropic maintains that Fable 5’s potential dangers are mitigated by safety protocols redirecting certain queries.
Anthropic highlighted the risks of releasing an advanced model, cautioning that, without protections, its features could be misused with severe repercussions.
Cryptocurrency users continue to express concern. Despite assurances, the industry has witnessed a surge in stolen digital assets, with losses reaching $629.7 million due to cyber-attacks in April, a figure unmatched since February 2025.
Simon Dedic, of Moonrock Capital, claims that Fable 5 may drastically reduce the barriers to finding exploitable flaws in smart contracts. Moonrock Capital specializes in venture capital investments in digital currencies.
Dedic warned DeFi projects that unsecured protocols might soon be exploited more frequently, emphasizing the risk associated with unaudited or copied projects.
Is DeFi at a Significant Risk?
Dedic recommends users adopt measures like revoking permissions, minimizing protocol-held assets, and utilizing new hardware wallets for crypto storage. Such steps reflect a deeper fear of security breaches, especially in smaller, less audited projects.
Conversely, Curve Finance’s Michael Egorov suggested that Mythos’ success in identifying software vulnerabilities might not threaten DeFi to the same extent. Many smart contracts are relatively short in code compared to other programs, making them less complex to assess.
Mini glossary: OpSec, an abbreviation for operational security, involves everyday practices to secure sensitive data and access systems. Multisig refers to wallets needing multiple confirmations for transactions.
According to Egorov, possible dangers more likely involve operational security failings than DeFi code infallibilities. He cited issues such as compromised keys or attacks on software dependencies as pivotal concerns, suggesting these represent distinct threats beyond code exploitation alone.
Will Restricted Access Be the Solution?
Anthropic is set to introduce a more sophisticated variant of the Claude Mythos 5 model, known as Project Glasswing, to a chosen group of cybersecurity companies. This iteration will include modifications in safeguards. Recently, the Mythos model has been credited with significant vulnerability detections across critical projects, crucial to open-source and crypto governance.
