CVE-2018-16882

A use-after-free issue was found in the way the Linux kernel’s KVM
hypervisor processed posted interrupts when nested(=1) virtualization is
enabled. In nested_get_vmcs12_pages(), in case of an error while processing
posted interrupt address, it unmaps the ‘pi_desc_page’ without resetting
‘pi_desc’ descriptor address, which is later used in
pi_test_and_clear_on(). A guest user/process could use this flaw to crash
the host kernel resulting in DoS or potentially gain privileged access to a
system. Kernel versions before 4.14.91 and before 4.19.13 are vulnerable.

Notes