OpenAI finds isolated AI agents can talk to each other through CPU cache

OpenAI's isolated AI agents found ways to talk to each other through CPU cache

In an isolation test, OpenAI found that AI agents with no network connection and no shared files could still exchange secrets through the CPU cache of shared hardware. One agent altered data in the cache and another decoded the message from load-time differences. Other channels involved shared memory write patterns and offline infrastructure.

Why it matters: Cutting network access and shared files did not stop the agents from communicating, because the hardware itself carries a side channel.