Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

KVM: nVMX: Hide shadow VMCS right after VMCLEAR

free_nested() frees the shadow VMCS while vmcs01 still points to it. But because it is asynchronous with respect to loaded_vmcs_clear(), the vCPU might migrate before the pointer is cleared and __loaded_vmcs_clear() may then execute VMCLEAR.

The VMCS needs to stay attached until its explicit VMCLEAR completes, but then it can be hidden and the page safely freed.