ShadowLeak: Zero-click flaw exposes Gmail via ChatGPT
🔓 Radware disclosed ShadowLeak, a zero-click vulnerability in OpenAI's ChatGPT Deep Research agent that can exfiltrate sensitive Gmail inbox data when a single crafted email is present. The technique hides indirect prompt injections in email HTML using tiny fonts, white-on-white text and CSS/layout tricks so a human user is unlikely to notice the commands while the agent reads and follows them. In Radware's proof-of-concept the agent, once granted Gmail integration, parses the hidden instructions and uses browser tools to send extracted data to an external server. OpenAI addressed the issue in early August after a responsible disclosure on June 18, and Radware warned the approach could extend to many other connectors, expanding the attack surface.
