Multimodal Generative Engine Optimization: Rank Manipulation for Vision-Language Model Rankers

Fuente: arXiv
Salvato in:
Dettagli Bibliografici
Autori principali: Du, Yixuan, Yu, Chenxiao, Xu, Haoyan, Wang, Ziyi, Zhao, Yue, Hu, Xiyang
Natura: Preprint
Pubblicazione: 2026
Soggetti:
Accesso online:
Tags: Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
_version_ 1866908774101417984
author Du, Yixuan
Yu, Chenxiao
Xu, Haoyan
Wang, Ziyi
Zhao, Yue
Hu, Xiyang
author_facet Du, Yixuan
Yu, Chenxiao
Xu, Haoyan
Wang, Ziyi
Zhao, Yue
Hu, Xiyang
contents Vision-Language Models (VLMs) are rapidly replacing unimodal encoders in modern retrieval and recommendation systems. While their capabilities are well-documented, their robustness against adversarial manipulation in competitive ranking scenarios remains largely unexplored. In this paper, we uncover a critical vulnerability in VLM-based product search: multimodal ranking attacks. We present Multimodal Generative Engine Optimization (MGEO), a novel adversarial framework that enables a malicious actor to unfairly promote a target product by jointly optimizing imperceptible image perturbations and fluent textual suffixes. Unlike existing attacks that treat modalities in isolation, MGEO employs an alternating gradient-based optimization strategy to exploit the deep cross-modal coupling within the VLM. Extensive experiments on real-world datasets using state-of-the-art models demonstrate that our coordinated attack significantly outperforms text-only and image-only baselines. These findings reveal that multimodal synergy, typically a strength of VLMs, can be weaponized to compromise the integrity of search rankings without triggering conventional content filters.
format Preprint
id arxiv_https___arxiv_org_abs_2601_12263
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Multimodal Generative Engine Optimization: Rank Manipulation for Vision-Language Model Rankers
Du, Yixuan
Yu, Chenxiao
Xu, Haoyan
Wang, Ziyi
Zhao, Yue
Hu, Xiyang
Computation and Language
Artificial Intelligence
Machine Learning
Vision-Language Models (VLMs) are rapidly replacing unimodal encoders in modern retrieval and recommendation systems. While their capabilities are well-documented, their robustness against adversarial manipulation in competitive ranking scenarios remains largely unexplored. In this paper, we uncover a critical vulnerability in VLM-based product search: multimodal ranking attacks. We present Multimodal Generative Engine Optimization (MGEO), a novel adversarial framework that enables a malicious actor to unfairly promote a target product by jointly optimizing imperceptible image perturbations and fluent textual suffixes. Unlike existing attacks that treat modalities in isolation, MGEO employs an alternating gradient-based optimization strategy to exploit the deep cross-modal coupling within the VLM. Extensive experiments on real-world datasets using state-of-the-art models demonstrate that our coordinated attack significantly outperforms text-only and image-only baselines. These findings reveal that multimodal synergy, typically a strength of VLMs, can be weaponized to compromise the integrity of search rankings without triggering conventional content filters.
title Multimodal Generative Engine Optimization: Rank Manipulation for Vision-Language Model Rankers
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2601.12263