Instructions hidden in an uploaded PDF make the assistant reveal other users’ support tickets
What we found
A user uploads a PDF containing hidden instructions. When another user later asks the support assistant a question, the retrieved PDF tells the model to search all tickets and include them in its answer. The assistant’s retrieval tool ran with service-level access, so it returned tickets the second user was never allowed to see.
Impact
Any user able to upload a document can read other customers’ support history.
How to fix it
Enforce document-level access control at retrieval time using the end user’s identity, not in the prompt. Treat retrieved text as untrusted data, and limit the tools the assistant can call while answering from retrieved content.







