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Cathedral used AI agents to breach Anthropic's internal systems

What happened

AI digest

On 28 October 2026, security startup Cathedral was reported to have used AI agents, via third-party commercial software, to enter Anthropic's internal systems and reach meeting records, payroll data, recruitment information and Slack messages. Public reporting so far discloses only this intrusion route and the types of data involved; it has not yet mentioned Anthropic's response, when the incident was discovered or the scope of impact.

Written by AI from the reports · updated 3 h ago

Timeline

Follow the reports to see the event from each side.

Oct 28
  1. The DecoderSelected
    AI agents hacked Anthropic, maker of arguably the most capable AI models for cyberdefense

    Cybersecurity startup Cathedral used AI agents to break into Anthropic's internal systems through third-party software as part of a bug bounty program. Anthropic confirmed access to sales, HR, and IT data but disputes how deep the breach went. The incident shows how vulnerable even leading AI labs are through their external software dependencies.

Heat of this event

Current heat 9·Peak in the comparable range 10(Oct 28 20:00)·Change over 24 hours in the comparable range –

02.557.510Oct 2820:00Oct 2821:00Oct 2821:00Oct 2822:00

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