ChatGPT Accused of Cross-Site Tracking via __obi Cookie

Security researcher Buchodi reverse-engineered OpenAI's ad platform (codenamed bazaar) and found that ChatGPT uses a cookie called obi to link users' third-party browsing and purchase history to their accounts for up to a year, with the findings trending on Hacker News.

2026-09-21 ~ 2026-09-21 · 3 related posts

• OpenAI's __obi ad tracker links your off-site browsing to your ChatGPT account — emax · 2026-09-21
• Researcher: ChatGPT's __obi cookie links your off-site shopping data back to your account — 新智元 · 2026-09-21
• ChatGPT's __obi cookie links your browsing on other sites to your OpenAI account, researcher finds — 机器之心 · 2026-09-21