It would seem so: https://www.theregister.com/security/2026/07/29/word-worm-crawls-into-copilot-spreads-chaos/5280588

It makes sense: with LLMs and agents based on them, even plain text becomes effectively executable, so any document can carry malicious instructions. It's worse with complex document formats like DOCX, ODT, or PDF, since text can be hidden from the human eye and escape detection by review. Very risky tech...