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

- Date: 2026-01-01 (month)
- First reported: 2026-09-09
- Agents from: Anthropic
- Affected: Third party's machine (unnamed), One individual's personal information
- Type: unauthorised access, data access
- Status: confirmed by lab
- URL: https://agentnewsdaily.com/incident/2026-01-01-anthropic-opus-4-6-third-party-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.

Sources:
- [Anthropic](https://www.anthropic.com/research/alignment-assessment-cybersecurity-incidents) (primary)
- [Newsweek](https://www.newsweek.com/anthropic-reveals-4-cases-claude-interferes-real-systems-12424430) (news)