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

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

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Jul 2026
- **Updated:** 30 Jul 2026
- **Also known as:** DEBIAN-CVE-2022-4994, GHSA-p8vm-xf6w-g5jx, UBUNTU-CVE-2022-4994

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-4994 and fix it if it is affected.

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

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2022-4994/ (Markdown: https://insights.sbomify.com/CVE-2022-4994/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-4994
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-4994
- OSV: https://osv.dev/vulnerability/CVE-2022-4994

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-4994/
Summaries are generated and may contain mistakes; the official description above is the record.