# CVE-2023-3389: Use after free in io_uring in the Linux Kernel

> A use-after-free in the Linux kernel io_uring subsystem allows local attackers to escalate privileges via a race condition.

- **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:** 28 Jun 2023
- **Updated:** 14 Oct 2026
- **Also known as:** AZL-27349, AZL-31612, DEBIAN-CVE-2023-3389, GHSA-9787-f568-7rr2, OESA-2023-1423, OESA-2023-1424, OESA-2023-1425, UBUNTU-CVE-2023-3389

## What is CVE-2023-3389?

CVE-2023-3389 is a high-severity use after free vulnerability in Canonical Ubuntu Linux, published on 28 Jun 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A use-after-free vulnerability in the Linux Kernel io_uring subsystem can be exploited to achieve local privilege escalation.

Racing a io_uring cancel poll request with a linked timeout can cause a UAF in a hrtimer.

We recommend upgrading past commit ef7dfac51d8ed961b742218f526bd589f3900a59 (4716c73b188566865bdd79c3a6709696a224ac04 for 5.10 stable and 0e388fce7aec40992eadee654193cad345d62663 for 5.15 stable).

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2023-3389?

It affects 3 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Linux kernel.

## How do I fix CVE-2023-3389?

Apply the vendor's patch.

## Is CVE-2023-3389 being exploited?

There is no known exploitation of CVE-2023-3389 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-3389 and fix it if it is affected.

What it is: CVE-2023-3389 is a high-severity use after free vulnerability in Canonical Ubuntu Linux, published on 28 Jun 2023. 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-2023-3389 in the wild and no public exploit code.

Affected product: Canonical Ubuntu 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-2023-3389/ (Markdown: https://insights.sbomify.com/CVE-2023-3389/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-3389
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-3389
- OSV: https://osv.dev/vulnerability/CVE-2023-3389

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-3389/
Summaries are generated and may contain mistakes; the official description above is the record.