# CVE-2023-0266: Linux Kernel Use-After-Free

> A use-after-free in the Linux Kernel ALSA PCM package allows local attackers to escalate privileges to ring0 access.

- **Severity:** High 7.9 (`CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:C/C:L/I:H/A:H`)
- **Exploited in the wild:** Yes, since 30 Mar 2023 (CISA KEV)
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Jan 2023
- **Updated:** 21 Oct 2025
- **Also known as:** A-265303544, AZL-13190, AZL-13229, DEBIAN-CVE-2023-0266, GHSA-h8jm-3c82-6vvq, OESA-2023-1198, OESA-2023-1199, OESA-2023-1200, OESA-2023-1201, PUB-A-265303544, RHSA-2023:1588, RHSA-2023:1590, UBUNTU-CVE-2023-0266

## What is CVE-2023-0266?

CVE-2023-0266 is a high-severity use after free vulnerability in Debian Debian Linux, published on 30 Jan 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 exists in the ALSA PCM package in the Linux Kernel. SNDRV_CTL_IOCTL_ELEM_{READ|WRITE}32 is missing locks that can be used in a use-after-free that can result in a priviledge escalation to gain ring0 access from the system user. We recommend upgrading past commit 56b88b50565cd8b946a2d00b0c83927b7ebb055e

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2023-0266?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `bpftool` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `bpftool-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-abi-whitelists` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-core` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-debug` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-debug-core` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-debug-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-debug-devel` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-debug-modules` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-debug-modules-extra` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-debuginfo-common-ppc64le` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-debuginfo-common-x86_64` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-devel` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-doc` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-modules` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-modules-extra` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-tools` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-tools-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kernel-tools-libs` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `kpatch-patch-4_18_0-147_74_1` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-4.el8_1 |
| `kpatch-patch-4_18_0-147_74_1-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-4.el8_1 |
| `kpatch-patch-4_18_0-147_74_1-debugsource` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-4.el8_1 |
| `kpatch-patch-4_18_0-147_76_1` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-3.el8_1 |
| `kpatch-patch-4_18_0-147_76_1-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-3.el8_1 |
| `kpatch-patch-4_18_0-147_76_1-debugsource` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-3.el8_1 |
| `kpatch-patch-4_18_0-147_77_1` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-3.el8_1 |
| `kpatch-patch-4_18_0-147_77_1-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-3.el8_1 |
| `kpatch-patch-4_18_0-147_77_1-debugsource` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-3.el8_1 |
| `kpatch-patch-4_18_0-147_78_1` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-2.el8_1 |
| `kpatch-patch-4_18_0-147_78_1-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-2.el8_1 |
| `kpatch-patch-4_18_0-147_78_1-debugsource` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-2.el8_1 |
| `kpatch-patch-4_18_0-147_80_1` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-1.el8_1 |
| `kpatch-patch-4_18_0-147_80_1-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-1.el8_1 |
| `kpatch-patch-4_18_0-147_80_1-debugsource` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:1-1.el8_1 |
| `perf` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `perf-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `python3-perf` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |
| `python3-perf-debuginfo` | Red Hat:rhel_e4s:8.1::baseos | All versions | 0:4.18.0-147.81.1.el8_1 |

Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2023-0266?

Apply the vendor's patch. US federal agencies must fix it by 20 Apr 2023.

## Is CVE-2023-0266 being exploited?

Yes. Attackers have exploited CVE-2023-0266 in the wild since at least 30 Mar 2023.

Public exploit code:

- Demo showing Claude Opus does not find CVE-2023-0266 (github_poc): https://github.com/SeanHeelan/claude_opus_cve_2023_0266

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-0266 and fix it if it is affected.

What it is: CVE-2023-0266 is a high-severity use after free vulnerability in Debian Debian Linux, published on 30 Jan 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2023-0266 in the wild since at least 30 Mar 2023.

Affected product: Debian Debian 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-2023-0266/ (Markdown: https://insights.sbomify.com/CVE-2023-0266/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-0266
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-0266
- OSV: https://osv.dev/vulnerability/CVE-2023-0266

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-0266/
Summaries are generated and may contain mistakes; the official description above is the record.