What is the largest security risk in a SDN?

I'm curious to know, what do you consider to be the biggest security risk in a Software-Defined Networking (SDN) environment? With the increasing reliance on virtualization and automation, it's crucial to understand the potential vulnerabilities and how they can be mitigated. Is it the potential for unauthorized access to the network due to a lack of proper access controls? Or could it be the complexity of managing multiple security policies across different layers of the SDN architecture? I'd love to hear your thoughts on this matter.