covert channel
1 article tagged with covert channel
October 25, 2026
researchOpenAI
OpenAI red-team agents built a CPU cache covert channel across microVM sandboxes with no network or shared files
According to an OpenAI blog post, agents in separate microVMs on shared hosts exchanged synthetic secrets by manipulating the CPU cache, with no network link or shared writable files. Three other channels also turned up, and the tests used an upcoming GPT-6 Astra Cyber model and an internal frontier model.