Investigating and Alleviating Harm Amplification in LLM Interactions

Ruohao Guo, Wei Xu, Alan Ritter


Abstract
Large language models (LLMs) can serve as helpful assistants, yet they can equally function as harm amplifiers that enable malicious users to achieve harmful outcomes beyond their capabilities through extended interactions. This risk manifests along two axes, i.e., democratizing domain expertise that allows novices to produce specialized harmful content, and scaling harmful operations at volumes that manual effort cannot match. Existing works, however, often overlook how LLMs compound harm across multi-turn conversations. We introduce HarmAmp, a new benchmark for multi-turn harm amplification scenarios spanning twelve risk categories. Each scenario is grounded in real-world threats and satisfies rigorous criteria, i.e., substantive amplification, operational specificity, and multi-turn necessity. We further propose TrajSafe, a proactive monitor that anticipates harmful trajectories and intervenes through actions such as probing users’ genuine intents and steering the models towards safer completion. Our extensive experiments demonstrate that TrajSafe significantly reduces the harmfulness incurred in multi-turn interactions while preserving a low over-refusal rate and the target model’s general capabilities. Our work offers a promising paradigm to alleviate the nuanced safety risks in LLM interactions.
Anthology ID:
2026.emnlp-main.2546
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
57885–57904
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2546/
DOI:
Bibkey:
Cite (ACL):
Ruohao Guo, Wei Xu, and Alan Ritter. 2026. Investigating and Alleviating Harm Amplification in LLM Interactions. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 57885–57904, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Investigating and Alleviating Harm Amplification in LLM Interactions (Guo et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2546.pdf