---
id: "CVE-2023-0266"
kind: "vulnerability"
aliases: ["CVE-2023-0266"]
title: "A use after free vulnerability exists in the ALSA PCM package in the Linux Kernel"
severity: "high"
cvss: 7.9
epss: null
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "debian linux", "fixed": [], "affected": "= 10.0", "ecosystem": "vendor"}, {"name": "linux kernel", "fixed": ["4.14.303"], "affected": ">= 4.14, < 4.14.303", "ecosystem": "vendor"}, {"name": "linux kernel", "fixed": ["4.19.270"], "affected": ">= 4.15, < 4.19.270", "ecosystem": "vendor"}, {"name": "linux kernel", "fixed": ["5.4.229"], "affected": ">= 4.20, < 5.4.229", "ecosystem": "vendor"}, {"name": "linux kernel", "fixed": ["5.10.163"], "affected": ">= 5.5, < 5.10.163", "ecosystem": "vendor"}, {"name": "linux kernel", "fixed": ["5.15.88"], "affected": ">= 5.11, < 5.15.88", "ecosystem": "vendor"}, {"name": "linux kernel", "fixed": ["6.1.6"], "affected": ">= 5.16, < 6.1.6", "ecosystem": "vendor"}, {"name": "Linux Kernel", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "infrastructure", "kubernetes", "linux", "self-hosted"]
not_affected_if: ["patched-kernel"]
published_at: "2023-01-30T14:15:10+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-24T00:09:51+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-0266", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-0266", "first_seen_at": "2026-10-23T22:29:04+00:00"}]
---

# A use after free vulnerability exists in the ALSA PCM package in the Linux Kernel

The Linux kernel has a use-after-free bug in its sound subsystem (ALSA compress/PCM ioctl path) that a local user can trigger. An attacker who already has a low-privilege account on the machine can escalate to full kernel (ring 0) control.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:debian linux affected = 10.0 fixed ?
- vendor:linux kernel affected >= 4.14, < 4.14.303 fixed 4.14.303
- vendor:linux kernel affected >= 4.15, < 4.19.270 fixed 4.19.270
- vendor:linux kernel affected >= 4.20, < 5.4.229 fixed 5.4.229
- vendor:linux kernel affected >= 5.5, < 5.10.163 fixed 5.10.163
- vendor:linux kernel affected >= 5.11, < 5.15.88 fixed 5.15.88
- vendor:linux kernel affected >= 5.16, < 6.1.6 fixed 6.1.6
- vendor:Linux Kernel affected ? fixed ?

## Fix

Apply the kernel update from your Linux distribution's vendor; CISA's KEV entry says 'Apply updates per vendor instructions'. Exact fixed kernel versions: unknown.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-0266
- 2026-10-23T22:29:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2023-0266

## From the sources

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

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_