Security researchers used Claude to hack into OpenAI's systems

Three independent security researchers at Hacktron say they broke into OpenAI employee accounts in under 72 hours using Anthropic's Claude Opus 4.8 and 5, the Wall Street Journal reports. Exploiting a flaw in how the third-party forum service Discourse processes HEIF images, they reached OpenAI's GitHub repository "Monorepo," said to hold the company's algorithmic secrets. They did not access internal code but proved entry with a pull request sent from an employee's Codex account. According to Hacktron, Claude Opus 5 launched on the evening of July 24, and by 10AM the next day they had used it to achieve the breach.