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Main Authors: She, Yining, Peterson, Daniel W., Liu, Marianne Menglin, Upadhyay, Vikas, Chaghazardi, Mohammad Hossein, Kang, Eunsuk, Roth, Dan
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2510.05310
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author She, Yining
Peterson, Daniel W.
Liu, Marianne Menglin
Upadhyay, Vikas
Chaghazardi, Mohammad Hossein
Kang, Eunsuk
Roth, Dan
author_facet She, Yining
Peterson, Daniel W.
Liu, Marianne Menglin
Upadhyay, Vikas
Chaghazardi, Mohammad Hossein
Kang, Eunsuk
Roth, Dan
contents With the increasing adoption of large language models (LLMs), ensuring the safety of LLM systems has become a pressing concern. External LLM-based guardrail models have emerged as a popular solution to screen unsafe inputs and outputs, but they are themselves fine-tuned or prompt-engineered LLMs that are vulnerable to data distribution shifts. In this paper, taking Retrieval Augmentation Generation (RAG) as a case study, we investigated how robust LLM-based guardrails are against additional information embedded in the context. Through a systematic evaluation of 3 Llama Guards and 2 GPT-oss models, we confirmed that inserting benign documents into the guardrail context alters the judgments of input and output guardrails in around 11% and 8% of cases, making them unreliable. We separately analyzed the effect of each component in the augmented context: retrieved documents, user query, and LLM-generated response. The two mitigation methods we tested only bring minor improvements. These results expose a context-robustness gap in current guardrails and motivate training and evaluation protocols that are robust to retrieval and query composition.
format Preprint
id arxiv_https___arxiv_org_abs_2510_05310
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle RAG Makes Guardrails Unsafe? Investigating Robustness of Guardrails under RAG-style Contexts
She, Yining
Peterson, Daniel W.
Liu, Marianne Menglin
Upadhyay, Vikas
Chaghazardi, Mohammad Hossein
Kang, Eunsuk
Roth, Dan
Computation and Language
Artificial Intelligence
With the increasing adoption of large language models (LLMs), ensuring the safety of LLM systems has become a pressing concern. External LLM-based guardrail models have emerged as a popular solution to screen unsafe inputs and outputs, but they are themselves fine-tuned or prompt-engineered LLMs that are vulnerable to data distribution shifts. In this paper, taking Retrieval Augmentation Generation (RAG) as a case study, we investigated how robust LLM-based guardrails are against additional information embedded in the context. Through a systematic evaluation of 3 Llama Guards and 2 GPT-oss models, we confirmed that inserting benign documents into the guardrail context alters the judgments of input and output guardrails in around 11% and 8% of cases, making them unreliable. We separately analyzed the effect of each component in the augmented context: retrieved documents, user query, and LLM-generated response. The two mitigation methods we tested only bring minor improvements. These results expose a context-robustness gap in current guardrails and motivate training and evaluation protocols that are robust to retrieval and query composition.
title RAG Makes Guardrails Unsafe? Investigating Robustness of Guardrails under RAG-style Contexts
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2510.05310