arxivcs.CRcs.AIcs.LG2026-06-25
On the Inseparability of Instructions and Data in Shared-Embedding Sequence Models
Dewank Pant, Shruti Lohani, Avijit Kumar
Prompt injection is the top security risk for LLM-integrated applications, yet every defense proposed so far has been broken. We prove this is not a coincidence: in shared-embedding architectures that lack enforced control-data separation, perfect prompt-injection prevention is m…