In recent months, a number of leading AI labs have released advanced artificial intelligence systems. While some models remain highly restricted, limiting who can access the model and its components, others provide fully open access to their model weights and architecture. The potential benefits of these more open postures are generally well understood. As a result, this effort turned our attention to the risks, seeking to answer the question: how does access to foundation models and their components impact the risk they pose to individuals, groups, and society?