Accessing the RAM of a QEMU Emulated System from Another Process

The title sounds like its a vulnerability that allows a random process access to qemu memory but it is not.

Its a 2021 tutorial that describes how to configure qemu to share memory between a host process and a qemu machine through /dev/shm.

Yes every hypervisor has this "feature" unless it uses CPU features to protect memory, such as encrypted VM memory available on newer AMD CPUs (SEV) : https://www.qemu.org/docs/master/system/i386/amd-memory-encr...

There is rather large ecosystem of tooling for poking and peeking the insides of VMs, usually called "VMI" (virtual machine introspection). kvm-vmi is one such example, but there are many others https://github.com/KVM-VMI/kvm-vmi

There's a library [1] that implements message passing and locking for communiction between VMs in a similar way and is used by the awesome looking glass project to send the accelerated GPU video stream from a vm to the host or a different vm.

[1] https://github.com/gnif/LGMP