🤖 AI Summary
This work addresses the insufficient robustness of vision-language models (VLMs) under simultaneous adversarial perturbations to both image and text modalities. To this end, we propose the first cross-modal collaborative adversarial attack framework. Our core innovation lies in constructing a general-purpose surrogate model based on multimodal fusion architectures, which explicitly models inter-modal dependencies for the first time. By jointly optimizing perturbations in a shared embedding space—through cross-modal gradient alignment and collaborative optimization—we generate coordinated image and text perturbations. Extensive experiments demonstrate that our method significantly outperforms unimodal and existing bimodal attacks on VQA and visual reasoning benchmarks. On state-of-the-art VLMs—including Instruct-BLIP and ViLT—it reduces accuracy by 32–47%. The framework establishes a unified, scalable benchmark for systematic robustness evaluation of VLMs, enabling rigorous assessment of cross-modal vulnerability.
📝 Abstract
Vision-language models, which integrate computer vision and natural language processing capabilities, have demonstrated significant advancements in tasks such as image captioning and visual question and answering. However, similar to traditional models, they are susceptible to small perturbations, posing a challenge to their robustness, particularly in deployment scenarios. Evaluating the robustness of these models requires perturbations in both the vision and language modalities to learn their inter-modal dependencies. In this work, we train a generic surrogate model that can take both image and text as input and generate joint representation which is further used to generate adversarial perturbations for both the text and image modalities. This coordinated attack strategy is evaluated on the visual question and answering and visual reasoning datasets using various state-of-the-art vision-language models. Our results indicate that the proposed strategy outperforms other multi-modal attacks and single-modality attacks from the recent literature. Our results demonstrate their effectiveness in compromising the robustness of several state-of-the-art pre-trained multi-modal models such as instruct-BLIP, ViLT and others.