# CVE-2023-52439: uio: Fix use-after-free in uio_open

> A race condition in the Linux kernel UIO driver allows a local attacker to trigger a use-after-free, potentially leading to code execution or privilege escalation.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 20 Feb 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-52439, DEBIAN-CVE-2023-52439, GHSA-7gq6-cq6r-rrpx, UBUNTU-CVE-2023-52439

## What is CVE-2023-52439?

CVE-2023-52439 is a high-severity use after free vulnerability in Linux kernel, published on 20 Feb 2024. 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:

uio: Fix use-after-free in uio_open

core-1				core-2
-------------------------------------------------------
uio_unregister_device		uio_open
				idev = idr_find()
device_unregister(&idev->dev)
put_device(&idev->dev)
uio_device_release
				get_device(&idev->dev)
kfree(idev)
uio_free_minor(minor)
				uio_release
				put_device(&idev->dev)
				kfree(idev)
-------------------------------------------------------

In the core-1 uio_unregister_device(), the device_unregister will kfree
idev when the idev->dev kobject ref is 1. But after core-1
device_unregister, put_device and before doing kfree, the core-2 may
get_device. Then:
1. After core-1 kfree idev, the core-2 will do use-after-free for idev.
2. When core-2 do uio_release and put_device, the idev will be double
   freed.

To address this issue, we can get idev atomic & inc idev reference with
minor_lock.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2023-52439?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-52439?

Apply the vendor's patch.

## Is CVE-2023-52439 being exploited?

There is no known exploitation of CVE-2023-52439 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-52439 and fix it if it is affected.

What it is: CVE-2023-52439 is a high-severity use after free vulnerability in Linux kernel, published on 20 Feb 2024. 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-2023-52439 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2023-52439/ (Markdown: https://insights.sbomify.com/CVE-2023-52439/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-52439
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-52439
- OSV: https://osv.dev/vulnerability/CVE-2023-52439

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-52439/
Summaries are generated and may contain mistakes; the official description above is the record.