A Multimodal Automatic Redteaming Evaluation based on Atomic Jailbreak Strategy Decoupling and Combination

Shiji Zhao, Yuxuan Zhou, Chen Xiong, Dongxian Wu, Yang Bai, Xun Chen


Abstract
Multimodal Large Language Models (MLLMs) have achieved impressive progress in image-text comprehension and generation, yet they remain susceptible to jailbreak attacks that can trigger harmful outputs and pose serious safety concerns. Existing multimodal jailbreak attacks have shown the feasibility of such attacks, but they still face two fundamental challenges: the lack of a atomic multi-modal strategy space, the absence of a concise and efficient executable framework beyond human-craft experience. To address these challenges, we first decompose the text-image jailbreak strategy space into three levels: structural, semantic, and syntactic, constructing a jailbreak strategy set encompassing both text and image modalities to systematically achieve combined coverage of different attack types. Then we propose a multimodal automated red team jailbreak method named Hierarchical Atomic Combination Attack (HACA). Specifically, based on a six-dimensional strategy space, a cross-modal joint planner is used to select and combine the different atomic jailbreak strategy for subsequent jailbreak command generation. Finally, at the implementation level, we explore to apply a unified generate executor to directly generate jailbreak instructions based on the selected multi-modal strategies. A series of experiments show that our automated red team method can achieve an attack success rate of average 95.48% against five mainstream MLLMs.
Anthology ID:
2026.emnlp-main.1616
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:
36733–36748
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1616/
DOI:
Bibkey:
Cite (ACL):
Shiji Zhao, Yuxuan Zhou, Chen Xiong, Dongxian Wu, Yang Bai, and Xun Chen. 2026. A Multimodal Automatic Redteaming Evaluation based on Atomic Jailbreak Strategy Decoupling and Combination. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 36733–36748, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
A Multimodal Automatic Redteaming Evaluation based on Atomic Jailbreak Strategy Decoupling and Combination (Zhao et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1616.pdf