Transfer Safety Awareness for Cross-Modal Safety Drift in Multimodal Large Language Models

Tianqi Xiao, Shiyao Cui, Minghao Zhang, Junxiao Yang, Renmiao Chen


Abstract
Visual modality enhances the capabilities of Multimodal Large Language Models (MLLMs) but also introduces a safety concern: a benign textual query may convey harmful intent when grounded in a visual image. We term this as cross-modal safety drift, and our pilot studies show that the safety response rate for such requests is substantially lower than that for requests containing explicitly unsafe text. This paper aims to systematically study this issue. First, we conduct an empirical analysis to identify representative unsafe response patterns. Building on these, we interpret model representations and attentions, revealing that visually risky cues receive limited attention and weakly trigger refusal. Motivated by the observation that safety signals from unsafe text processing can be transferred, we propose safety-awareness representation transfer (SRT), a lightweight direction-refinement method that mitigates cross-modal safety drift while freezing the MLLM backbone. Experiments across benchmarks and models show that SRT effectively improves safety in diverse cross-modal settings while preserving utility.
Anthology ID:
2026.findings-emnlp.638
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:
13375–13391
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.638/
DOI:
10.18653/2026.findings-emnlp.638
Bibkey:
Cite (ACL):
Tianqi Xiao, Shiyao Cui, Minghao Zhang, Junxiao Yang, and Renmiao Chen. 2026. Transfer Safety Awareness for Cross-Modal Safety Drift in Multimodal Large Language Models. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 13375–13391, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Transfer Safety Awareness for Cross-Modal Safety Drift in Multimodal Large Language Models (Xiao et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.638.pdf