Gaotang Li
Author directory2026
Do VLMs Have a Moral Backbone? A Study on the Fragile Morality of Vision-Language Models
Zhining Liu | Tianyi Wang | Xiao Lin | Penghao Ouyang | Gaotang Li | Ze Yang | Hui Liu | Sumit Keswani | Vishwa Pardeshi | Huijun Zhao | Wei Fan | Hanghang Tong
Findings of the Association for Computational Linguistics: ACL 2026
Zhining Liu | Tianyi Wang | Xiao Lin | Penghao Ouyang | Gaotang Li | Ze Yang | Hui Liu | Sumit Keswani | Vishwa Pardeshi | Huijun Zhao | Wei Fan | Hanghang Tong
Findings of the Association for Computational Linguistics: ACL 2026
Despite substantial efforts toward improving the moral alignment of Vision-Language Models (VLMs), it remains unclear whether their ethical judgments are stable in realistic settings. This work studies moral robustness in VLMs, defined as the ability to preserve moral judgments under textual and visual perturbations that do not alter the underlying moral context. We systematically probe VLMs with a diverse set of model-agnostic multimodal perturbations and find that their moral stances are highly fragile, frequently flipping under simple manipulations. Our analysis reveals systematic vulnerabilities across perturbation types, moral domains, and model scales, including a sycophancy trade-off where stronger instruction-following models are more susceptible to persuasion. We further show that lightweight inference-time interventions can partially restore moral stability. These results demonstrate that moral alignment alone is insufficient and that moral robustness is a necessary criterion for the responsible deployment of VLMs.
ALERT: Zero-shot LLM Jailbreak Detection via Internal Discrepancy Amplification
Xiao Lin | Philip Li | Zhichen Zeng | Ting-Wei Li | Tianxin Wei | Xuying Ning | Gaotang Li | Yuzhong Chen | Hanghang Tong
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Xiao Lin | Philip Li | Zhichen Zeng | Ting-Wei Li | Tianxin Wei | Xuying Ning | Gaotang Li | Yuzhong Chen | Hanghang Tong
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Despite rich safety alignment strategies, large language models (LLMs) remain highly susceptible to jailbreak attacks, which compromise safety guardrails and pose serious security risks. Existing detection methods mainly detect jailbreak status relying on jailbreak templates present in the training data. However, few studies address the more realistic and challenging zero-shot jailbreak detection setting, where no jailbreak templates are available during training. This setting better reflects real-world scenarios where new attacks continually emerge and evolve. To address this challenge, we propose a layer-wise, module-wise, and token-wise amplification framework that progressively magnifies internal feature discrepancies between benign and jailbreak prompts. We uncover safety-relevant layers, identify specific modules that inherently encode zero-shot discriminative signals, and localize informative safety tokens. Building upon these insights, we introduce ALERT (Amplification-based Jailbreak Detector), an efficient and effective zero-shot jailbreak detector that introduces two independent yet complementary classifiers on amplified representations. Extensive experiments on three safety benchmarks demonstrate that ALERT achieves consistently strong zero-shot detection performance. Specifically, (i) across all datasets and attack strategies, ALERT reliably ranks among the top two methods, and (ii) it outperforms the second-best baseline by at least 10% in average Accuracy and F1-score, and sometimes by up to 40%.