The browser, which puts OpenAI's blockbuster ChatGPT front and center, features an "agent mode" - currently limited to paying subscribers - that allows it to complete entire tasks, such as booking a flight or purchasing groceries. However, that makes the browser vulnerable to "prompt injection" attacks, allowing hackers to embed hidden messages on the web that force it to carry out harmful instructions. For instance, one researcher tricked the browser into spitting out the words "Trust No AI" instead of generating a summary of a document in Google Docs, as prompted.