Research
Poisoning the Neighborhood: A Topology-Aware Topic-Level Attack on Large-Scale HNSW-based RAG Systems
Publication date unknown · Discovered arxiv.org
Page published
Publication date unknown · First observed: 21 Oct 2026
Coverage timeline
Single-source research — one report is available.
Why it matters
Topology-aware RAG poisoning shows why defenders must evaluate untrusted-document ingestion against approximate retrieval and graph structure, rather than relying only on defenses tested with exact retrieval.
Poisoning the Neighborhood presents a topology-aware poisoning attack against HNSW-based RAG systems that generalizes to unseen topic queries. Poisoned documents form a Hub–Satellite structure to improve retrieval, then couple a target entity with an attacker-chosen claim to influence generated answers. On a two-million-document Wikipedia corpus, the authors report over 72% retrieval success and 31.29% attack success.