Use after free in SNDRV_CTL_IOCTL_ELEM in Linux Kernel
Affects the Linux kernel from 4.14 onward, specifically the 32-bit compatibility path in the ALSA control code where controls_rwsem was missing. CVSS scores it 7.9 (high). The fix is commit 56b88b50565cd8b946a2d00b0c83927b7ebb055e.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Actively exploited
- Fix
- Fix or patch referenced
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The Linux kernel's ALSA sound subsystem (its PCM and control interface, specifically the SNDRV_CTL_IOCTL_ELEM read and write calls) is affected. A local user could exploit a memory handling flaw there to escalate privileges to full kernel-level (ring 0) access.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original 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
Timeline
- CVE published
- Added to CISA KEV
CISA has evidence of exploitation in the wild
- CISA remediation deadline
Due date for US federal agencies to patch
- Record last updated
Affected versions
- ALSA pcm
From 4.14 · fixed in 56b88b50565cd8b946a2d00b0c83927b7ebb055e
References 4
GitHub · torvalds/linux
lists.debian.org
Questions about CVE-2023-0266
What does this mean?
The bug is a use-after-free: memory in the ALSA control code can be used after it has been released. It sits in the SNDRV_CTL_IOCTL_ELEM handling, in the 32-bit compatibility path where a lock (controls_rwsem) was missing. The facts provided do not describe the resulting impact.Source: git.kernel.org
Am I affected, and how do I check?
Linux kernel versions from 4.14 up to the commit 56b88b50565cd8b946a2d00b0c83927b7ebb055e that fixed it. Only the 32-bit compatibility path (snd_ctl_ioctl_compat, ctl_elem_write_read) is named as affected. To check a system, compare the running kernel version from uname -r against the fixed kernel releases in your distribution's advisory.Source: git.kernel.org
What should I do about it?
Update to a kernel release that includes commit 56b88b50565cd8b946a2d00b0c83927b7ebb055e, using the update channel from your distribution or kernel.org stable releases. The facts do not name a specific fixed version number.Source: git.kernel.org
Is it being exploited?
Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-03-30, which means it has evidence of attacks. No public exploit code is tracked.Source: cisa.gov, cve.now feed data