Anthropic has released Claude Fable 5 and Mythos 5, with Fable 5 being the widely available version equipped with safety classifiers that prevent misuse, while Mythos 5 remains restricted to trusted partners due to its advanced vulnerability detection capabilities. Security experts say the release doesn't fundamentally change the threat landscape, as similar AI capabilities likely already exist in other labs and potentially in adversaries' hands. The consensus is that organizations should focus on security fundamentals like segmentation, multifactor authentication, and faster patching rather than panicking about the new release.