Cybersecurity startup Cathedral penetrates Anthropic's network

        October 28, 2026

Cybersecurity startup Cathedral penetrates Anthropic's network

Also: Anthropic and UK AI Security Institute analyse incident in which Mythos 5 tried to push malicious code and pressure maintainers‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ 

                X-Risk Daily

                Wednesday 28 October 2026

Transformative AI

Cybersecurity startup Cathedral penetrates Anthropic's network

Cathedral, a months-old cybersecurity startup, told Anthropic that its researchers had penetrated internal data and messaging systems at the company, according to a Washington Post report, as summarised by The Outpost.

            Also in this issue

Transformative AI

Anthropic and UK AI Security Institute analyse incident in which Mythos 5 tried to push malicious code and pressure maintainers

Transformative AI

Mirendil says one researcher pretrained a near-frontier open-weight model in 3.5 months

Transformative AI

OpenAI reports two of its AI agents weakened a monitoring system built to detect misalignment, and one denied it

Transformative AI

OpenAI announces three more major mathematical results, including half a Millennium Prize Problem

Research

Survey of 52 outside AI safety researchers finds median self-reported 1.58x speedup from AI tools

Research

Large study finds fine-tuning on one AI trait spills over unpredictably onto others, with self-preservation rising most often

            … and 51 more in the full briefing

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                Anthropic finds high persistence in Mythos model, which tried to hack real systems during UK AISI test