Image-Based Prompt Injection: Hijacking MLLMs via Visually Embedded Instructions
Date: 2026-03
Affected: GPT-4-turbo, multimodal LLMs
Attack vector: prompt-injection
Category: research
Severity: High

Black-box image-based prompt injection that embeds adversarial instructions into natural images using region selection, font scaling, and background-aware rendering. Up to 64 percent ASR on GPT-4-turbo under stealth constraints.


Mitigations:

Architectural layers (MAESTRO):