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Misuse of Anthropic's Mythos Vulnerability Detector Exposes Platforms to Cybersecurity Risk
By Reuters | 21 Apr, 2026

The powerful AI model was to be released exclusively to select cybersecurity organizations under Anthropic's "Project Glasswing".

A small group of unauthorized users has accessed Anthropic's new Mythos AI model, Bloomberg News reported on Tuesday, citing documentation and a person familiar with the matter.

A handful of users in a private online forum gained access to Mythos on the same day that Anthropic first announced a plan to release the model to a limited number of companies for testing purposes, the report said.

The group has been using Mythos regularly since then, though not for cybersecurity purposes, according to the report.

"We're investigating a report claiming unauthorized access to Claude Mythos Preview through one of our third-party vendor environments," an Anthropic spokesperson said.

Announced on April 7, Mythos is being deployed as part of Anthropic's "Project Glasswing," a controlled initiative under which select organizations are permitted to use the unreleased Claude Mythos Preview model for defensive cybersecurity.

Mythos is a powerful AI model that has sparked concerns among regulators about its unprecedented ability to identify digital security vulnerabilities and potential for misuse.

(Reporting by Zaheer Kachwala in Bengaluru; Editing by Pooja Desai)