Poisoning the Neighborhood: A Topology-Aware Topic-Level Attack on Large-Scale HNSW-based RAG Systems
The paper introduces a topology-aware poisoning attack against large-scale HNSW-RAG systems that generalizes to unseen topic queries. The attack structures poisoned documents into Hubs and Satellites to create competitive entry points and local cohesion. This method successfully maintains high retrieval success rates even when dealing with budget-constrained search and unseen queries, exposing structural vulnerabilities in HNSW.