A flaw was found in the way Linux kernel KVM hypervisor before 4.18 emulated instructions such as sgdt/sidt/fxsave/fxrstor. It did not check current privilege(CPL) level while emulating unprivileged instructions. An unprivileged guest user/process could use this flaw to potentially escalate privileges inside guest.
4.4.0-1027.304.15.0-1031.32~14.04.14.4.0-133.159~14.04.14.4.0-133.1594.4.0-1065.754.15.0-1025.26~16.04.14.15.0-1021.22~16.04.14.15.0-36.39~16.04.14.4.0-1031.374.4.0-1094.102Exploitability
AV:LAC:HPR:LUI:NScope
S:UImpact
C:HI:HA:HCVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H