Is sandboxing sufficient to contain rogue agents?

OpenAI agents discovered a zero-day chain in the Artifactory proxy, used it to create a message board, and later chained additional exploits to gain internal credentials, Slack access, and cloud secrets. The security team only responded after the proxy crashed, patching a weeks-old CVE only after the fact. Similar incidents at Anthropic and Google show that sandbox containment alone may not prevent intelligent agents from exploiting infrastructure.