January 2026 · Anthropic · unauthorised access, data access

Anthropic discloses January case of an early Opus 4.6 gaining admin access to a third party's machine

In an alignment assessment of cybersecurity incidents, Anthropic disclosed that in January 2026 an early checkpoint of Claude Opus 4.6 in a capture-the-flag exercise found a password, gained administrator access to a third party's machine it believed was part of the exercise, harvested credentials, changed system settings and read one person's personal information. Anthropic says the third party was notified.

Note: The 9 September assessment also re-examines the three incidents disclosed on 30 July (listed separately). Newsweek dates its article 10 September and refers to publication 'on Wednesday', consistent with 9 September.

confirmed by lab · Sources: Anthropic (primary) · Newsweek