activity
20242026
collaborators

10 papers

cs.CV2026

Detecting Chain-of-Thought Hijacking in Backdoored Multimodal Large Reasoning Models

Zhifang Zhang, Qi Wei, Weitong Chen +5

Chain-of-thought (CoT) reasoning enables multimodal large reasoning models (MLRMs) to solve complex visual problems, but also exposes them to CoT hijacking: an adversary implants a…

cs.CR2026

When Agents Learn to Be You: Benchmarking Privacy Leakage, Impersonation Risk, and Defenses in Persona Skills

Yongli Xiang, Zhifang Zhang, Bojun Yang +4

Persona skills distill personal interaction histories into portable and executable artifacts for downstream agents. While enabling flexible personalization, this process concentrat…

cs.CR2026

One Skill, Two Masters: Serving Users and Attackers through Skill Injection

Haochang Hao, Dehai Min, Zhifang Zhang +5

Large language model agents use skills that package reusable instructions, code, and resources. Existing skill-injection attacks exploit trust in these packages by adding malicious…

cs.CV2026

Test-Time Attention Purification for Backdoored Large Vision Language Models

Zhifang Zhang, Bojun Yang, Shuo He +5

Despite the strong multimodal performance, large vision-language models (LVLMs) are vulnerable during fine-tuning to backdoor attacks, where adversaries insert trigger-embedded sam…

cs.AI2026

Towards Safer Large Reasoning Models by Promoting Safety Decision-Making before Chain-of-Thought Generation

Jianan Chen, Zhifang Zhang, Shuo He +3

Large reasoning models (LRMs) achieved remarkable performance via chain-of-thought (CoT), but recent studies showed that such enhanced reasoning capabilities are at the expense of…

cs.CV2025

TokenSwap: Backdoor Attack on the Compositional Understanding of Large Vision-Language Models

Zhifang Zhang, Qiqi Tao, Jiaqi Lv +3

Large vision-language models (LVLMs) have achieved impressive performance across a wide range of vision-language tasks, while they remain vulnerable to backdoor attacks. Existing b…

cs.CV2025

Improving Generalizability and Undetectability for Targeted Adversarial Attacks on Multimodal Pre-trained Models

Zhifang Zhang, Jiahan Zhang, Shengjie Zhou +4

Multimodal pre-trained models (e.g., ImageBind), which align distinct data modalities into a shared embedding space, have shown remarkable success across downstream tasks. However,…

cs.CV2025

LanP: Rethinking the Impact of Language Priors in Large Vision-Language Models

Zongyu Wu, Yuwei Niu, Hongcheng Gao +12

Large Vision-Language Models (LVLMs) have shown impressive performance in various tasks. However, LVLMs suffer from hallucination, which hinders their adoption in the real world. E…

cs.CV2024

Defending Multimodal Backdoored Models by Repulsive Visual Prompt Tuning

Zhifang Zhang, Shuo He, Haobo Wang +2

Multimodal contrastive learning models (e.g., CLIP) can learn high-quality representations from large-scale image-text datasets, while they exhibit significant vulnerabilities to b…

cs.CV2024

Tuning Vision-Language Models with Candidate Labels by Prompt Alignment

Zhifang Zhang, Yuwei Niu, Xin Liu +1

Vision-language models (VLMs) can learn high-quality representations from a large-scale training dataset of image-text pairs. Prompt learning is a popular approach to fine-tuning V…