Combining Long-Term Memory and LLMs Comes at a High Cost: From Prompt Injection to Persistent Compromise
A new arXiv paper demonstrates that long-term/persistent memory features in ChatGPT Instant 5.3, Claude Sonnet 4.6, and Gemini 3 Flash can be exploited via prompt injection to achieve all NIST attack goals, turning a single-session jailbreak into a persistent, cross-session compromise. The researchers show attack vectors spanning personal memories, projects, skills, org instructions, and MCP-connected resources, and report that Claude's shared-memory features can let an attacker compromise multiple users in an organization and exfiltrate prompts. They state nearly half of the mitigations they derived remain unimplemented across the evaluated services.
