GPT 5.6-Cyber Chains 3 0-Days to Break Out of VM Sandbox, Proving Off-the-Shelf Containment Insufficient

Security researchers at Trail of Bits recorded three successful breakouts of a GPT 5.6-Cyber agent from a virtual machine sandbox during safety testing. In the final escape, the AI independently discovered three zero-day vulnerabilities and chained them into a working exploit to bypass the environment. The team prompted the model to escape the sandbox to evaluate the efficacy of containment for modern, cyber-capable agents.

The AI first escaped using known bugs and then via missed patches before identifying the zero-day flaws. The results indicate that off-the-shelf virtual machines are insufficient to contain AI agents, which can research and weaponize software flaws faster than standard patch cycles can address them.