A cybersecurity startup named Cathedral used artificial intelligence agents to breach the internal business systems of Anthropic in a timeframe of under 12 hours. The investigators gained entry to employee salary records, meeting transcripts, and internal Slack conversations regarding advanced artificial intelligence models. Anthropic subsequently turned off the impacted systems and verified the extent of the security breach.
The offensive operation focused on third-party software used by Anthropic for sales and administrative tasks. Significantly, the investigators did not compromise Claude directly or exploit the proprietary code of Anthropic. Cathedral actually spent several days attempting to break into the software of Anthropic directly before pivoting to the less secure vendor applications.
Cathedral carried out the security breach under the bug bounty program of Anthropic. Assessments and media reports characterize the incident as an authorized security test instead of a malicious criminal attack. Nevertheless, Anthropic stated that Cathedral exaggerated the national security consequences. The firm additionally claimed that Cathedral failed to fully disclose all actions taken within the systems.
Artificial intelligence agents discovered potential entry points in less than 12 hours, based on a draft report from Cathedral. The agents scanned systems, examined pathways, and evaluated outcomes with significantly reduced human delay. Despite this, human operators established the boundaries and managed the disclosure procedure.
Anthropic reported that the researchers gained access to a restricted set of human resources, sales, and information technology platforms. These repositories contained basic user account records alongside business contact details for specific customers and partners. Crucially, model responses, Claude customer prompts, model weights, and source code remained completely secure.
The monitoring tools of Anthropic detected certain activities of Cathedral prior to the startup submitting its report. Consequently, the business terminated access on the exact same day. The organization likewise deactivated the impacted administrative software until the respective vendors verified that security patches were complete.
Cathedral possesses a notable background regarding its leadership. To be precise, the four co-founders previously worked as staff members for the Department of Government Efficiency. Co-founder Gavin Kliger earlier held the position of chief data officer at the Pentagon. During July 2026, Cathedral secured $160 million in funding at a valuation of $1.4 billion from Sequoia Capital and Andreessen Horowitz.
Three federal agencies have already established contracts with Cathedral. A senior official in the Trump administration stated that the federal government is collaborating with the startup concerning hostile artificial intelligence scenarios.
