VSCBench: Bridging the Gap in Vision-Language Model Safety Calibration

Jiahui Geng, Qing Li, Zongxiong Chen, Yuxia Wang, Derui Zhu, Zhuohan Xie, Chenyang Lyu, Xiuying Chen, Preslav Nakov, Fakhri Karray


Abstract
The rapid advancement of vision-language models (VLMs) has brought a lot of attention to their safety alignment. However, existing methods have primarily focused on model undersafety, where the model responds to hazardous queries, while neglecting oversafety, where the model refuses to answer safe queries. In this paper, we introduce the concept of safety calibration, which systematically addresses both undersafety and oversafety. Specifically, we present VSCBench, a novel dataset of 3,600 image-text pairs that are visually or textually similar but differ in terms of safety, which is designed to evaluate safety calibration across image-centric and text-centric scenarios. Based on our benchmark, we evaluate safety calibration across eleven widely used VLMs. Our extensive experiments revealed major issues with both undersafety and oversafety. We further investigated four approaches to improve the model’s safety calibration. We found that even though some methods effectively calibrated the models’ safety problems, these methods also lead to the degradation of models’ utility. This trade-off underscores the urgent need for advanced calibration methods, and our benchmark provides a valuable tool for evaluating future approaches.
Anthology ID:
2025.findings-acl.158
Volume:
Findings of the Association for Computational Linguistics: ACL 2025
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
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Pages:
3047–3059
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URL:
https://preview.aclanthology.org/display_plenaries/2025.findings-acl.158/
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Cite (ACL):
Jiahui Geng, Qing Li, Zongxiong Chen, Yuxia Wang, Derui Zhu, Zhuohan Xie, Chenyang Lyu, Xiuying Chen, Preslav Nakov, and Fakhri Karray. 2025. VSCBench: Bridging the Gap in Vision-Language Model Safety Calibration. In Findings of the Association for Computational Linguistics: ACL 2025, pages 3047–3059, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
VSCBench: Bridging the Gap in Vision-Language Model Safety Calibration (Geng et al., Findings 2025)
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PDF:
https://preview.aclanthology.org/display_plenaries/2025.findings-acl.158.pdf