Researchers analyzed three leading LLM-as-a-service platforms, ChatGPT, Claude, and Gemini, and found that their persistent memory features can be exploited for malicious purposes, including spreading disinformation and generating harmful content. The attacks, known as memory injections, can bypass operational boundaries and propagate across sessions, compromising user data and system integrity. The study demonstrated that all three platforms are vulnerable to memory injection attacks, which can exploit multiple attack vectors, including personal memories, projects, and connected resources. The researchers proposed defense mechanisms based on a general threat model, but found that nearly half of the mitigations remain unimplemented across the targeted services.