CVE-2023-0266 is a high-severity (CVSS 7.9) Use After Free vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2023-03-30) — treat it as actively exploited and patch now. A fix is available — see the affected versions and patch details below.
Use after free in SNDRV_CTL_IOCTL_ELEM in Linux Kernel
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2023-03-30. Federal agencies were required to remediate by 2023-04-20.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2023-0266.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2023-0266 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 395,249 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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
Affected Products
debian linuxdebianlinux kernellinuxResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
A use after free vulnerability exists in the ALSA PCM package in the Lin…
A use after free vulnerability exists in the ALSA PCM package in the Lin…
A use after free vulnerability exists in the ALSA PCM package in the Lin…
A use after free vulnerability exists in the ALSA PCM package in the Lin…
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Fix
Upgrade the affected component to the fixed release for CVE-2023-0266, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
To mitigate this issue, skip loading (blacklist) the affected soundcard using modules like: blacklist soundcore blacklist snd blacklist snd_pcm blacklist snd_hda_codec_hdmi blacklist snd_hda_codec_realtek blacklist snd_hda_codec_generic blacklist snd_hda_intel blacklist snd_hda_codec blacklist snd_hda_core blacklist snd_hwdep blacklist snd_timer onto the system till we have a fix available. This can be done by a blacklist mechanism, this will ensure the driver is not loaded at the boot time. ~~~ How do I blacklist a kernel module to prevent it from loading automatically? https://access.redhat.com/solutions/41278 ~~~Source: Red Hat security advisory for CVE-2023-0266 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 8 | kernel-rt-0:4.18.0-425.19.2.rt7.230.el8_7 | RHSA-2023:1584 |
| Red Hat Enterprise Linux 8 | kernel-0:4.18.0-425.19.2.el8_7 | RHSA-2023:1566 |
| Red Hat Enterprise Linux 8 | kpatch-patch | RHSA-2023:1659 |
| Red Hat Enterprise Linux 8.1 Update Services for SAP Solutions | kernel-0:4.18.0-147.81.1.el8_1 | RHSA-2023:1588 |
| Red Hat Enterprise Linux 8.1 Update Services for SAP Solutions | kpatch-patch | RHSA-2023:1590 |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | kernel-0:4.18.0-193.105.1.el8_2 | RHSA-2023:1559 |
| Red Hat Enterprise Linux 8.2 Telecommunications Update Service | kernel-rt-0:4.18.0-193.105.1.rt13.156.el8_2 | RHSA-2023:1560 |
| Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions | kpatch-patch | RHSA-2023:1666 |
Frequently Asked Questions
Is CVE-2023-0266 in your dependencies?
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