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

Q: How do I fix CVE-2023-0266?

debian linux: mitigate or apply the listed mitigation; linux kernel: upgrade to 4.14.303, 4.19.270, 5.4.229, 5.10.163, 5.15.88, 6.1.6. Exact commands for each OS are on this page.

Q: Is CVE-2023-0266 being exploited?

Yes. CVE-2023-0266 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

Q: What does CVE-2023-0266 affect?

CVE-2023-0266 affects debian linux, linux kernel. Severity is high (CVSS 7.9). 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 fro

Q: How urgent is CVE-2023-0266?

Priority 85/100. High severity; Exploited in the wild (CISA KEV); Public exploit reference; On your watchlist

Patch now

HIGH 7.9EXPLOITEDWATCHLISTMITIGATEUPGRADE

CVE-2023-0266 is a high-severity flaw (CVSS 7.9) affecting debian linux, linux kernel, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity
Exploited in the wild (CISA KEV)
Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.9 (High)
Attack vector	Adjacent network
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	3.7% (top 10%)
CISA exploited list	Yes, fix due 2023-04-20
Weakness	CWE-416
Published	2023-01-30
Last modified	2026-06-17

Publisher (CNA): Google Inc. · Vendor: debian · linux

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-01-30 14:15 UTCPublished CVE record published
2023-03-30Exploited Added to the CISA Known Exploited Vulnerabilities list
2023-04-20Deadline CISA due date for US federal agencies to patch
2026-06-17 05:25 UTCUpdated Record last modified

debian debian linux MITIGATE

Affected: 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

linux linux kernel UPGRADE

Affected: >= 4.14 and < 4.14.303 · >= 4.15 and < 4.19.270 · >= 4.20 and < 5.4.229 · >= 5.5 and < 5.10.163 · >= 5.11 and < 5.15.88 · >= 5.16 and < 6.1.6

Fixed in: 4.14.303, 4.19.270, 5.4.229, 5.10.163, 5.15.88, 6.1.6

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora ELN · python-wrapt · FIXED · 2.5.2-1.eln159 · FEDORA-2026-5503ee9370 · source

sudo dnf upgrade --advisory=FEDORA-2026-5503ee9370

Fedora 46 · python-wrapt · FIXED · 2.5.2-1.fc46 · FEDORA-2026-8a83579801 · source

sudo dnf upgrade --advisory=FEDORA-2026-8a83579801

Ubuntu 22.04 · linux · FIXED · 5.15.0-69.76

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.15.0-69.76" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 20.04 · linux · FIXED · 5.4.0-144.161

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.4.0-144.161" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · linux · NOT AFFECTED

Ubuntu 24.10 · linux · NOT AFFECTED

Ubuntu 25.04 · linux · NOT AFFECTED

Debian 12 · linux · FIXED · 6.1.7-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.1.7-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · linux · FIXED · 6.1.7-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.1.7-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 8 · kernel-rt · FIXED · kernel-rt-4.18.0-425.19.2.rt7.230.el8_7

sudo dnf upgrade --advisory=RHSA-2023:1584 rpm -q kernel-rt

RHEL 8 · kernel · FIXED · kernel-4.18.0-425.19.2.el8_7

sudo dnf upgrade --advisory=RHSA-2023:1566 rpm -q kernel

RHEL 8.1 Update Services for SAP Solutions · kernel · FIXED · kernel-4.18.0-147.81.1.el8_1

sudo dnf upgrade --advisory=RHSA-2023:1588 rpm -q kernel

RHEL 8.2 Advanced Update Support · kernel · FIXED · kernel-4.18.0-193.105.1.el8_2

sudo dnf upgrade --advisory=RHSA-2023:1559 rpm -q kernel

RHEL 8.2 Telecommunications Update Service · kernel-rt · FIXED · kernel-rt-4.18.0-193.105.1.rt13.156.el8_2

sudo dnf upgrade --advisory=RHSA-2023:1560 rpm -q kernel-rt

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: SeanHeelan/claude_opus_cve_2023_0266 (17 stars)

Verify at the official source NVD · CVE Program · CISA KEV catalog · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-0266?

debian linux: mitigate or apply the listed mitigation; linux kernel: upgrade to 4.14.303, 4.19.270, 5.4.229, 5.10.163, 5.15.88, 6.1.6. Exact commands for each OS are on this page.

Is CVE-2023-0266 being exploited?

Yes. CVE-2023-0266 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

What does CVE-2023-0266 affect?

CVE-2023-0266 affects debian linux, linux kernel. Severity is high (CVSS 7.9). 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 fro

How urgent is CVE-2023-0266?

Priority 85/100. High severity; Exploited in the wild (CISA KEV); Public exploit reference; On your watchlist

Software pages

Linux kernel vulnerabilities · Debian vulnerabilities

Related CVEs

CVE-2026-111497 CRITICAL 9.8 EXPLOITED UPGRADE UPGRADE Google Brotli Unchecked Return Value Vulnerability
CVE-2023-2462 MEDIUM 4.3 UPGRADE MITIGATE Inappropriate implementation in Prompts in Google Chrome prior to 113.0.5672.63 allowed a remote attacker to o
CVE-2023-2468 MEDIUM 4.3 UPGRADE MITIGATE Inappropriate implementation in PictureInPicture in Google Chrome prior to 113.0.5672.63 allowed a remote atta
CVE-2023-52356 HIGH 7.5 MITIGATE UPGRADE A segment fault (SEGV) flaw was found in libtiff that could be triggered by passing a crafted tiff file to the
CVE-2026-41082 HIGH 7.3 UPGRADE MITIGATE In OCaml opam before 2.5.1, a .install field containing a destination filepath can use ../ to reach a parent d

References

← Back to latest CVEs