The term “Random memory access” is a horribly confusing misnomer from before I was born. It’s used as a contrast with sequential memory access, to mean memory can be accessed in any arbitrary order.

My understanding is that these vulnerabilities allow reading the memory at arbitrary mapped pointers, from the perspective of the CPU, in kernel or user space. So you could use the kernel’s data structures to figure out what other programs are mapped, and where, and go read their memory.