# CVE-2023-54034: iommufd: Make sure to zero vfio_iommu_type1_info before copying to user

> A local attacker can read uninitialized kernel memory via the iommufd subsystem due to missing zero initialization in vfio_iommu_type1_info.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-54034, GHSA-47gj-cqh4-pq8c, UBUNTU-CVE-2023-54034

## What is CVE-2023-54034?

CVE-2023-54034 is a vulnerability in Linux, published on 24 Dec 2025. 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:

iommufd: Make sure to zero vfio_iommu_type1_info before copying to user

Missed a zero initialization here. Most of the struct is filled with
a copy_from_user(), however minsz for that copy is smaller than the
actual struct by 8 bytes, thus we don't fill the padding.

## Which versions are affected by CVE-2023-54034?


## How do I fix CVE-2023-54034?

Apply the vendor's patch.

## Is CVE-2023-54034 being exploited?

There is no known exploitation of CVE-2023-54034 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-54034 and fix it if it is affected.

What it is: CVE-2023-54034 is a vulnerability in Linux, published on 24 Dec 2025. 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-2023-54034 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-2023-54034/ (Markdown: https://insights.sbomify.com/CVE-2023-54034/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-54034
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-54034
- OSV: https://osv.dev/vulnerability/CVE-2023-54034

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-54034/
Summaries are generated and may contain mistakes; the official description above is the record.