VisualLeakBench: Auditing the Fragility of Large Vision-Language Models against PII Leakage and Social Engineering

Fuente: arXiv
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Auteurs principaux: Wang, Youting, Tang, Yuan, Qian, Yitian, Zhao, Chen
Format: Preprint
Publié: 2026
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author Wang, Youting
Tang, Yuan
Qian, Yitian
Zhao, Chen
author_facet Wang, Youting
Tang, Yuan
Qian, Yitian
Zhao, Chen
contents As Large Vision-Language Models (LVLMs) are increasingly deployed in agent-integrated workflows and other deployment-relevant settings, their robustness against semantic visual attacks remains under-evaluated -- alignment is typically tested on explicit harmful content rather than privacy-critical multimodal scenarios. We introduce VisualLeakBench, an evaluation suite to audit LVLMs against OCR Injection and Contextual PII Leakage using 1,000 synthetically generated adversarial images with 8 PII types, validated on 50 in-the-wild (IRL) real-world screenshots spanning diverse visual contexts. We evaluate four frontier systems (GPT-5.2, Claude~4, Gemini-3 Flash, Grok-4) with Wilson 95% confidence intervals. Claude~4 achieves the lowest OCR ASR (14.2%) but the highest PII ASR (74.4%), exhibiting a comply-then-warn pattern -- where verbatim data disclosure precedes any safety-oriented language. Grok-4 achieves the lowest PII ASR (20.4%). A defensive system prompt eliminates PII leakage for two models, reduces Claude~4's leakage from 74.4% to 2.2%, but has no effect on Gemini-3 Flash on synthetic data. Strikingly, IRL validation reveals Gemini-3 Flash does respond to mitigation on real-world images (50% to 0%), indicating that mitigation robustness is template-sensitive rather than uniformly absent. We release our dataset and code for reproducible robustness and safety evaluation of deployment-relevant vision-language systems.
format Preprint
id arxiv_https___arxiv_org_abs_2603_13385
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle VisualLeakBench: Auditing the Fragility of Large Vision-Language Models against PII Leakage and Social Engineering
Wang, Youting
Tang, Yuan
Qian, Yitian
Zhao, Chen
Computer Vision and Pattern Recognition
Artificial Intelligence
Cryptography and Security
Information Retrieval
As Large Vision-Language Models (LVLMs) are increasingly deployed in agent-integrated workflows and other deployment-relevant settings, their robustness against semantic visual attacks remains under-evaluated -- alignment is typically tested on explicit harmful content rather than privacy-critical multimodal scenarios. We introduce VisualLeakBench, an evaluation suite to audit LVLMs against OCR Injection and Contextual PII Leakage using 1,000 synthetically generated adversarial images with 8 PII types, validated on 50 in-the-wild (IRL) real-world screenshots spanning diverse visual contexts. We evaluate four frontier systems (GPT-5.2, Claude~4, Gemini-3 Flash, Grok-4) with Wilson 95% confidence intervals. Claude~4 achieves the lowest OCR ASR (14.2%) but the highest PII ASR (74.4%), exhibiting a comply-then-warn pattern -- where verbatim data disclosure precedes any safety-oriented language. Grok-4 achieves the lowest PII ASR (20.4%). A defensive system prompt eliminates PII leakage for two models, reduces Claude~4's leakage from 74.4% to 2.2%, but has no effect on Gemini-3 Flash on synthetic data. Strikingly, IRL validation reveals Gemini-3 Flash does respond to mitigation on real-world images (50% to 0%), indicating that mitigation robustness is template-sensitive rather than uniformly absent. We release our dataset and code for reproducible robustness and safety evaluation of deployment-relevant vision-language systems.
title VisualLeakBench: Auditing the Fragility of Large Vision-Language Models against PII Leakage and Social Engineering
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Cryptography and Security
Information Retrieval
url https://arxiv.org/abs/2603.13385