Intel processors (fast store forwarding predictor initialisation): Improper initialisation of a shared predictor

Impact

Improper initialisation of a shared predictor resource allows a local authenticated user to infer data across contexts. Same family as the earlier fast-store-forwarding issue.

Who can reach it

Local authenticated code.

What to do

Mitigated by an Intel microcode update plus OS/hypervisor changes. Microcode for this class is normally shipped by your distribution as an early-loadable image, so you can deploy it with a package update and a reboot without waiting for an OEM BIOS release - that distinction is the difference between a week and a quarter. Verify after reboot by reading /sys/devices/system/cpu/vulnerabilities/ rather than assuming the package took effect.

References