A flaw was found in Linux kernel’s KVM virtualization subsystem. The VMX code does not restore the GDT.LIMIT to the previous host value, but instead sets it to 64KB. With a corrupted GDT limit a host’s userspace code has an ability to place malicious entries in the GDT, particularly to the per-cpu variables. An attacker can use this to escalate their privileges.
www.securityfocus.com/bid/104905
access.redhat.com/errata/RHSA-2018:2390
access.redhat.com/errata/RHSA-2018:2391
access.redhat.com/errata/RHSA-2018:2392
access.redhat.com/errata/RHSA-2018:2393
access.redhat.com/errata/RHSA-2018:2394
bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10901
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3444d7da1839b851eefedd372978d8a982316c36
help.ecostruxureit.com/display/public/UADCE725/Security+fixes+in+StruxureWare+Data+Center+Expert+v7.6.0
www.oracle.com/security-alerts/cpujul2020.html
www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html