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

Three researchers at the security firm Hacktron used Anthropic's Claude Opus 5 to chain two flaws and take over the ChatGPT and Codex accounts of several OpenAI employees, then reach an internal OpenAI code repository.

The chain began with a bug in the software that runs OpenAI's public help forum and moved through a weakness in OpenAI's own login system.

This was security research, not a real-world attack: the team reported the flaws to OpenAI, proved the access with a harmless pull request, and then stopped. From the first look, that internal access took under 72 hours.

OpenAI confirmed a fix about 14 hours after the report, according to Hacktron, and on September 1 paid the team a $6,500 bounty. OpenAI said the award "recognizes the OpenAI-side finding, not the actions against Discourse," the open-source software that runs the forum. Testing the forum itself was outside its bug bounty program.

OpenAI has not publicly described the login flaw, and it confirmed the finding through that fix and payment rather than by detailing the account takeovers.

Hacktron, which describes itself as an AI-assisted security research firm, was careful about what it did and did not do. When one employee's Codex link to OpenAI's code on GitHub was opened, it triggered a single pull request in the internal repository. It did not read any source code, merge or ship anything, or touch customer data.