A flaw was found in the way KVM hypervisor handled x2APIC Machine Specific Rregister (MSR) access with nested(=1) virtualization enabled. In that, L1 guest could access L0's APIC register values via L2 guest, when 'virtualize x2APIC mode' is enabled. A guest could use this flaw to potentially crash the host kernel resulting in DoS issue. Kernel versions from 4.16 and newer are vulnerable to this issue.
4.13.0-16.193.11.0-12.194.2.0-16.194.4.0-1002.24.4.0-1001.104.15.0-1001.14.15.0-1030.31~16.04.14.15.0-1023.24~14.04.14.11.0-1009.94.15.0-1002.24.15.0-1003.34.15.0-1004.44.15.0-1008.84.15.0-1009.94.15.0-1012.124.15.0-1013.134.15.0-1014.144.15.0-1018.184.15.0-1019.19+14 more4.18.0-1018.18~18.04.1Exploitability
AV:LAC:HPR:LUI:NScope
S:CImpact
C:NI:NA:HCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H