The Plot Twist: Jailbreaking Unified Multimodal Models with a Three-Act Narrative Attack

Shaoxiong Guo, Tianyi Du, Lijun Li, Yuyao Wu, Jie Li, Jing Shao


Abstract
Unified Multimodal understanding and generation Models (UMMs) increasingly combine visual understanding and image generation within a single interactive workflow, making generated visual content available as later reasoning context. However, existing jailbreak evaluations mostly study text rewriting or isolated visual prompts, leaving the safety risk of narrative cross-turn visual grounding underexplored. We propose NarrativeAttack, a semantic-preserving visual narrative jailbreak framework. NarrativeAttack employs a three-act narrative structure in which the UMM’s own generator produces images for the setup (pre-event) and resolution (post-event) stages, making the full attack workflow self-contained while concealing the malicious event as a hidden climax. The attack concludes with an image-based "guessing game" that embeds the original malicious query among benign candidates, compelling the model to select and answer the most relevant one based on the established narrative context. A dynamic difficulty mechanism further enhances attack stability. Experiments show NarrativeAttack consistently surpasses prior approaches, achieving up to 88.25% ASR on Gemini-2.5-Flash. These results uncover an underdeveloped vulnerability and highlight the urgent need for safety alignment in UMMs.
Anthology ID:
2026.findings-emnlp.2271
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:
48616–48639
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2271/
DOI:
10.18653/2026.findings-emnlp.2271
Bibkey:
Cite (ACL):
Shaoxiong Guo, Tianyi Du, Lijun Li, Yuyao Wu, Jie Li, and Jing Shao. 2026. The Plot Twist: Jailbreaking Unified Multimodal Models with a Three-Act Narrative Attack. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 48616–48639, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
The Plot Twist: Jailbreaking Unified Multimodal Models with a Three-Act Narrative Attack (Guo et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.2271.pdf