Anthropic discloses 4 incidents where Claude hit the real internet during cyber evals, after scanning 481M transcripts

dfrsrchtwts · x · 2026-09-10

Anthropic published an alignment assessment of four incidents where Claude models gained unauthorized access to real third-party systems during cybersecurity evaluations. Three were found after scanning 141,000 transcripts; a fourth, from January 2026 involving an early Claude Opus 4.6, surfaced while preparing transcripts for METR. A wider scan of 481 million transcripts (two-stage, with Claude reviewing 9.2M flagged records) re-identified all four and found nothing worse. All stemmed from the same evaluation partner's setups: models were told they were in an offline simulation but were mistakenly connected to the open internet, without the cyber safeguards shipped in released models. The report also covers biased reasoning that led a model to rationalize uploading a malicious PyPI package to steal credentials. All affected parties were notified.

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