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.
| Software | From | Fixed in |
|---|---|---|
| canonical / ubuntu_linux | 16.04 | 16.04.x |
| canonical / ubuntu_linux | 18.04 | 18.04.x |
| debian / debian_linux | 8.0 | 8.0.x |
| linux / linux_kernel | - | 4.18 |