CVE-2022-4994 KVM: x86: wean fast IN from emulator_pio_in

Not scored Published 30 Jul 2026 Updated 30 Jul 2026

A refactoring change in the Linux kernel KVM module that has no functional impact or security vulnerability.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2022-4994?

CVE-2022-4994 is a vulnerability in Linux, published on 30 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86: wean fast IN from emulator_pio_in

Use __emulator_pio_in() directly for fast PIO instead of bouncing through emulator_pio_in() now that __emulator_pio_in() fills "val" when handling in-kernel PIO. vcpu->arch.pio.count is guaranteed to be '0', so this a pure nop.

emulator_pio_in_emulated is now the last caller of emulator_pio_in.

No functional change intended.

Which versions are affected by CVE-2022-4994?

How do I fix CVE-2022-4994?

Apply the vendor's patch.

Is CVE-2022-4994 being exploited?

There is no known exploitation of CVE-2022-4994 in the wild and no public exploit code.

Sources

Also known as DEBIAN-CVE-2022-4994, GHSA-p8vm-xf6w-g5jx, UBUNTU-CVE-2022-4994.