InjecMEM: Memory Injection Attack on LLM Agent Memory Systems

TL;DR - InjecMEM is a single-interaction memory injection attack that plants a retrievable record in an LLM agent’s persistent memory to steer later topic-related responses toward a chosen output. It exposes agent memory as a durable attack surface even without direct access to the memory store.

• Combines a retriever-agnostic anchor with high-recall topical cues and an adversarial command that activates when the record is retrieved.
• Optimizes the command using gradient-based coordinate search across synthetic prompt templates, insertion positions, and optionally multiple backbone models.
• Remains effective across multiple memory systems and models under variable contexts, long prompts, and memory drift.
• Targets related queries while reportedly leaving non-target queries unaffected, highlighting the need for memory-system defenses.