Defeating Cerberus: Concept-Guided Privacy-Leakage Mitigation in Multimodal Language Models

Fuente: arXiv
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Autori principali: Zhang, Boyang, Akkus, Istemi Ekin, Chen, Ruichuan, Dethise, Alice, Satzke, Klaus, Rimac, Ivica, Zhang, Yang
Natura: Preprint
Pubblicazione: 2025
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author Zhang, Boyang
Akkus, Istemi Ekin
Chen, Ruichuan
Dethise, Alice
Satzke, Klaus
Rimac, Ivica
Zhang, Yang
author_facet Zhang, Boyang
Akkus, Istemi Ekin
Chen, Ruichuan
Dethise, Alice
Satzke, Klaus
Rimac, Ivica
Zhang, Yang
contents Multimodal large language models (MLLMs) have demonstrated remarkable capabilities in processing and reasoning over diverse modalities, but their advanced abilities also raise significant privacy concerns, particularly regarding Personally Identifiable Information (PII) leakage. While relevant research has been conducted on single-modal language models to some extent, the vulnerabilities in the multimodal setting have yet to be fully investigated. In this work, we investigate these emerging risks with a focus on vision language models (VLMs), a representative subclass of MLLMs that covers the two modalities most relevant for PII leakage, vision and text. We introduce a concept-guided mitigation approach that identifies and modifies the model's internal states associated with PII-related content. Our method guides VLMs to refuse PII-sensitive tasks effectively and efficiently, without requiring re-training or fine-tuning. We also address the current lack of multimodal PII datasets by constructing various ones that simulate real-world scenarios. Experimental results demonstrate that the method can achieve an average refusal rate of 93.3% for various PII-related tasks with minimal impact on unrelated model performances. We further examine the mitigation's performance under various conditions to show the adaptability of our proposed method.
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id arxiv_https___arxiv_org_abs_2509_25525
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Defeating Cerberus: Concept-Guided Privacy-Leakage Mitigation in Multimodal Language Models
Zhang, Boyang
Akkus, Istemi Ekin
Chen, Ruichuan
Dethise, Alice
Satzke, Klaus
Rimac, Ivica
Zhang, Yang
Cryptography and Security
Machine Learning
Multimodal large language models (MLLMs) have demonstrated remarkable capabilities in processing and reasoning over diverse modalities, but their advanced abilities also raise significant privacy concerns, particularly regarding Personally Identifiable Information (PII) leakage. While relevant research has been conducted on single-modal language models to some extent, the vulnerabilities in the multimodal setting have yet to be fully investigated. In this work, we investigate these emerging risks with a focus on vision language models (VLMs), a representative subclass of MLLMs that covers the two modalities most relevant for PII leakage, vision and text. We introduce a concept-guided mitigation approach that identifies and modifies the model's internal states associated with PII-related content. Our method guides VLMs to refuse PII-sensitive tasks effectively and efficiently, without requiring re-training or fine-tuning. We also address the current lack of multimodal PII datasets by constructing various ones that simulate real-world scenarios. Experimental results demonstrate that the method can achieve an average refusal rate of 93.3% for various PII-related tasks with minimal impact on unrelated model performances. We further examine the mitigation's performance under various conditions to show the adaptability of our proposed method.
title Defeating Cerberus: Concept-Guided Privacy-Leakage Mitigation in Multimodal Language Models
topic Cryptography and Security
Machine Learning
url https://arxiv.org/abs/2509.25525