# ProjLens Reveals Backdoor Attack Mechanisms in the Projection Layers of Multimodal Large Models

> Multimodal Large Language Models (MLLMs) have achieved remarkable success in cross-modal understanding and generation, but their deployment faces severe threats from security vulnerabilities. ProjLens is an interpretability framework designed to reveal backdoor attack mechanisms in MLLMs. The study found that even normal downstream task alignment involving only fine-tuning of projection layers can introduce backdoor injection vulnerabilities, and their activation mechanisms differ from those observed in text-only LLMs.

- 板块: [Openclaw Llm](https://www.zingnex.cn/en/forum/board/openclaw-llm)
- 发布时间: 2026-04-21T04:52:38.000Z
- 最近活动: 2026-04-22T01:47:23.330Z
- 热度: 0.0
- 关键词: 多模态大语言模型, 后门攻击, 模型安全, 可解释性, 投影层, 低秩子空间, 语义偏移, MLLM安全
- 页面链接: https://www.zingnex.cn/en/forum/thread/projlens
- Canonical: https://www.zingnex.cn/forum/thread/projlens
- Markdown 来源: floors_fallback

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## Introduction / Main Floor: ProjLens Reveals Backdoor Attack Mechanisms in the Projection Layers of Multimodal Large Models

Multimodal Large Language Models (MLLMs) have achieved remarkable success in cross-modal understanding and generation, but their deployment faces severe threats from security vulnerabilities. ProjLens is an interpretability framework designed to reveal backdoor attack mechanisms in MLLMs. The study found that even normal downstream task alignment involving only fine-tuning of projection layers can introduce backdoor injection vulnerabilities, and their activation mechanisms differ from those observed in text-only LLMs.