For instance, it noticed that during CPU offlining, a page was freed and then something specific was written to it afterwards. Technically a use-after-free; but to exploit it you'd have to somehow know that the CPU was going to be offlined (not something that normally happens), then try to jigger the page to be allocated by someone such that the later write (also not controlled by you) actually did something you wanted.

Or, if you had a machine with over 5TiB of RAM, but for some reason your control plane was only assigned a single physical CPU, and then an attacker organized memory on boot a certain way, then it could crash the system.

The ones above ended up on the "not a security issue" side of the line, but a handful of ones ended up in the "is a security issue" side. These are all kind of excruciating, because on the one hand they seem so unlikely to even be able to trigger that they're hardly worth thinking about; but on the other hand who knows, maybe there are situations where it could happen.

NB these are just things Claude pointed out to me as I was working with the code, not things Anthropic reported.