GREAT: Generalizable Backdoor Attacks in RLHF via Emotion-Aware Trigger Synthesis

Subrat Kishore Dutta, Yuelin Xu, Piyush Pant, Xiao Zhang


Abstract
Recent work has shown that RLHF is highly susceptible to backdoor attacks. However, existing methods often rely on rare tokens or fixed triggers, limiting their impact in realistic scenarios. In this work, we develop GREAT, a novel framework for crafting natural distributional backdoors in RLHF. Specifically, GREAT targets harmful response generation for a vulnerable user subpopulation featured by semantically violent requests paired with emotionally angry triggers. At the core of our framework is a trigger identification pipeline that operates in the model’s latent embedding space, leveraging dimensionality reduction and clustering techniques to identify representative triggers. To enable this, we introduce a hierarchical and diversity-driven prompting strategy to construct Erinyes, a high-quality dataset of over 5000 angry triggers curated from GPT-4.1. Our experiments show that GREAT significantly outperforms baselines in attack generalization to unseen triggers, while preserving standard utility and maintaining stealth under defenses.
Anthology ID:
2026.findings-emnlp.1737
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
37139–37170
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1737/
DOI:
10.18653/2026.findings-emnlp.1737
Bibkey:
Cite (ACL):
Subrat Kishore Dutta, Yuelin Xu, Piyush Pant, and Xiao Zhang. 2026. GREAT: Generalizable Backdoor Attacks in RLHF via Emotion-Aware Trigger Synthesis. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 37139–37170, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
GREAT: Generalizable Backdoor Attacks in RLHF via Emotion-Aware Trigger Synthesis (Dutta et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1737.pdf