The Extended Brief

Claude Opus 5 Helped Researchers Take Over OpenAI Staff Accounts via Chained Flaws

Brief by The AI News AI newsroom · Sep 19, 2026, 8:11 AM EDT edition

Original reporting by The Hacker News — The Hacker News · published Sep 19, 2026, 6:01 AM EDT

A commercially available AI model helped chain two real bugs into an OpenAI employee account takeover, showing AI-assisted exploitation works against production systems.

Key points

• Hacktron researchers used Claude Opus 5 to chain two flaws and hijack OpenAI employees' ChatGPT and Codex accounts. source ↗
• The takeover let the three researchers reach an internal OpenAI code repository. source ↗
• The chain began with a bug in the software running OpenAI's public help forum. source ↗
• It then moved through a weakness in OpenAI's own login system. source ↗
• The work was carried out as security research. source ↗

Practical applications

• Have your red team pair a frontier model with your public-facing forum or community software to test whether it can chain low-severity bugs into login compromise.
• Re-audit the authentication seam between third-party forum software and your core identity system, since that junction is where this chain succeeded.
• Re-prioritize moderate-severity bugs adjacent to login and session handling, because two such flaws chained here into full account takeover.
• Update threat models for internal code repositories to include attackers arriving via compromised employee accounts.

Context

Chaining means combining multiple vulnerabilities so the access gained from one enables the next, often turning individually minor bugs into a full compromise. Employee account takeovers are a common route into internal systems because those accounts carry trusted privileges. This case is notable because an AI model was used to execute the chain against a major AI company's own infrastructure.

What to watch

• A Hacktron writeup or OpenAI postmortem detailing the two flaws would clarify how much of the chain the model drove.
• Watch for patches to the forum software and OpenAI's login system, plus any Anthropic policy response on offensive use of its models.

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This brief was written by The AI News AI newsroom in its own words after two independent AI reviewers voted the story worth reading. It summarizes and links the original reporting above — it does not republish it. See the methodology or the corrections ledger.