Blog Hacking OpenAI A heap overflow and SSO misconfiguration to compromise OpenAI internal repositories September 13, 2026 11 min read Intro On July 25, 2026, we chained two critical vulnerabilities to compromise multiple OpenAI employees’ ChatGPT accounts. With these accounts, we could then access internal OpenAI repositories, and potentially many other connectors. To prove we had in fact gained the access we believed without allowing ourselves to learn any sensitive information, we used the employee’s Codex to open a PR #1186742 in OpenAI’s internal monorepo openai/openai . Exploit chain libheif Image decoder Debian Missing security backport ImageMagick Uses libheif Discourse Image uploads OpenAI forum community.openai.com OpenAI SSO Identity flaw ChatGPT / Codex Account access GitHub Connected integration Internal repos OpenAI Until two months ago, any user or OpenAI employee logging into OpenAI’s own help forum ( community.openai.com ) could have had their ChatGPT and Codex accounts taken over.…