Spectre V2 is an indirect branch poisoning attack that can lead to data leakage.
An exploit for Spectre V2 tricks the indirect branch predictor into executing
code from a future indirect branch chosen by the attacker, even if the privilege
level is different.
Since Linux Kernel 4.15 you can check the Spectre V2 mitigation state with the following command:
cat /sys/devices/system/cpu/vulnerabilities/spectre_v2
Enforce the Spectre V2 mitigation by adding the argument
spectre_v2=on to the default
GRUB 2 command line for the Linux operating system.
Configure the default Grub2 kernel command line to contain spectre_v2=on) as follows:
# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) spectre_v2=on)"