LLM-based document re-rankers utilizing decoder-only and Mixture-of-Experts (MoE) architectures are vulnerable to candidate-embedded prompt injections during multi-document comparison tasks. By embedding Decision Objective Hijacking (DOH) or Decision Criteria Hijacking (DCH) prompts into candidate documents, attackers can manipulate the model's preference to artificially elevate an injected document to the top rank. The vulnerability exploits the models' instruction-following capabilities and…
Source: arXiv