In the Linux kernel, the following vulnerability has been resolved:
KVM: nVMX: Put vmcs12 pages if nested VM-Enter fails due to invalid guest state
Put all vmcs12 pages if KVM synthesizes a nested VM-Exit due to invalid guest while emulating VMLAUNCH or VMRESUME. The invalid guest state path doesnt use nested_vmx_vmexit() as that API is intended to be used if and only if L2 is active, and the open coded equivalent neglects to put the vmcs12 pages. Failure to put the vmcs12 pages leaks any pinned pages (and/or mappings) if L1 retries VMLAUNCH/VMRESUME.
Note, the !from_vmenter scenario doesnt suffer the same problem, as vmx_get_nested_state_pages() only gets/pins/maps the vmcs12 pages if L2 is active, i.e. if a full VM-Exit is guaranteed before KVM will retry getting vmcs12 pages.