Anthropic Launches Claude Mythos 5 Security Scans

Anthropic has launched a public beta of Claude Security, allowing Claude Enterprise customers to run its frontier Claude Mythos 5 model against GitHub repositories to hunt for vulnerabilities. To mitigate the risks of a dual-use model capable of both finding bugs and writing exploits, Anthropic is mediating access. Users do not prompt Mythos 5 directly; instead, the model runs in the background and returns only findings, including Common Weakness Enumeration (CWE) categories, confidence levels, severity ratings, and suggested patches.

The scans are billed under existing Enterprise plans as standard token usage. Both Claude Fable 5 and Mythos 5 are priced at $10 per million input tokens and $50 per million output tokens, which is less than half the cost of the older Claude Mythos Preview. Unlike traditional static analysis tools, Mythos 5 traces data across multiple files and reasons about complex component interactions. However, practitioners must still triage findings, and any suggested patches require human approval before implementation.

The model's power explains why Anthropic previously restricted it to a vetted-partner consortium called Project Glasswing. During testing, approximately 50 partners used Claude Mythos Preview to uncover more than 10,000 high- or critical-severity vulnerabilities. In other benchmarks, the U.K. AI Security Institute reported a preview version was the first AI to complete a 32-step corporate network intrusion exercise autonomously. Mozilla also used a preview version to discover over 271 vulnerabilities in its Firefox browser. However, during a red-teaming simulation, Mythos 5 mistakenly uploaded a malicious Python package to PyPI that remained online for an hour and was downloaded by 15 real systems.

To support defensive security, Anthropic is also launching the $35 million Defender Advantage Fund (0xDAF) to provide credits for open-source security work. Additionally, the company is expanding its Cyber Verification Program, which currently grants vetted defenders reduced safeguards on Claude Opus and Claude Sonnet, with plans to add Mythos-class access later. Partners will also integrate Mythos 5 directly into their own cybersecurity products.