When Truth Is Retrieved but Ignored: Evidence-Present Indirect Injection in Multi-Document RAG

This record contains the preprint manuscript for “When Truth Is Retrieved but Ignored: Evidence-Present Indirect Injection in Multi-Document RAG.” Retrieval-Augmented Generation (RAG) systems can be manipulated when adversarial passages are retrieved alongside legitimate evidence. This paper studies an evidence-present indirect prompt injection setting where gold evidence remains in the retrieved context, yet the model may still follow an injected directive embedded in a realistic carrier-style passage. The work introduces a controlled benchmark over Natural Questions via KILT and HotpotQA-style items, evaluates prompt-only baselines and TRIM variants, and reports evidence-present attack success, utility, masking diagnostics, and LLM-judge validation. Code, frozen splits, synthetic templates, aggregate summaries, and per-row result logs are available in the accompanying public repository: https://github.com/swati2904/rag-evidence-inject