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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 20 Apr 2023.
Debian LinuxOperating system · Debian

CVE-2023-0266

HIGH · 7.0 CVSS v3.1 Published 2023-01-30
Fix available
A fix is available. Upgrade to 4.14.303 / 4.19.270 or later.
See remediation →
96/100
Remediation priority · Urgent
In the wild Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A use-after-free vulnerability exists in the ALSA PCM sound driver in the Linux kernel. The SNDRV_CTL_IOCTL_ELEM_READ32 and SNDRV_CTL_IOCTL_ELEM_WRITE32 ioctl handlers lack proper locking mechanisms, allowing a local attacker to trigger a race condition and dangling pointer dereference. This enables privilege escalation from a standard user to ring0 (kernel) execution.

MitigationApply the upstream kernel fix by upgrading to a version containing commit 56b88b50565cd8b946a2d00b0c83927b7ebb055e, or backport the commit. This is a kernel-level fix requiring system reboot after deployment.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 10.0
Linux KernelOperating system
Affected:>= 4.14, < 4.14.303>= 4.15, < 4.19.270>= 4.20, < 5.4.229>= 5.5, < 5.10.163>= 5.11, < 5.15.88>= 5.16, < 6.1.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed kernel version
    Run `uname -r` or `cat /proc/version` to obtain the running kernel version
    Affected if The kernel version falls within any of these vulnerable ranges: 4.14.x before 4.14.303, 4.15.x through 4.19.x before 4.19.270, 4.20.x through 5.4.x before 5.4.229, 5.5.x through 5.10.x before 5.10.163, 5.11.x through 5.15.x before 5.15.88, or 5.16.x through 6.1.x before 6.1.6
  2. Check Debian kernel version
    On Debian 10 systems, run `dpkg -l | grep linux-image` to list installed kernel packages
    Affected if The installed kernel package version matches the vulnerable version ranges listed above for Linux Kernel
  3. Verify ALSA sound subsystem is present
    Check if the snd module or ALSA core is loaded by running `lsmod | grep snd` or checking /proc/asound/
    Affected if ALSA sound drivers are loaded or the /proc/asound/ directory exists (the vulnerability exists in the ALSA PCM core when 32-bit IOCTL handlers are accessed)

You are affected if your kernel version is within the vulnerable ranges AND the ALSA sound subsystem is present on your system.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.14.303 / 4.19.270 / 5.4.229 or later
Fixed in 4.14.3034.19.2705.4.229
Vendor patch git.kernel.org →
Interim mitigation

Apply the upstream kernel fix by upgrading to a version containing commit 56b88b50565cd8b946a2d00b0c83927b7ebb055e, or backport the commit. This is a kernel-level fix requiring system reboot after deployment.

Recommended fix High confidence

Linux Kernel 4.14.303+/4.19.270+/5.4.229+/5.10.163+ or any 5.11+ stable release

  1. Identify current kernel version with `uname -r`
  2. Upgrade Linux kernel to a fixed version: 4.14.303 or later for 4.14.x, 4.19.270 or later for 4.19.x, 5.4.229 or later for 5.4.x, 5.10.163 or later for 5.10.x, or any version 5.11 and above
  3. Update bootloader configuration if necessary using distribution-specific tools (e.g., update-grub for GRUB)
  4. Reboot the system to load the new kernel
  5. Verify kernel version after reboot with `uname -r` to confirm the fix is applied
Caveat Kernel upgrades may require rebuilding third-party kernel modules (like proprietary GPU drivers) and may introduce compatibility issues with older system utilities; ensure backups and test in non-production environments first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Debian Linux Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

Scan for this in your stack

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dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-0266 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data