CVE-2026-89979

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ALSA: pcm: Fix race between non-atomic ops and trigger-start

We protect the races of the concurrent state transitions between

atomic PCM ops, but the checks between the non-atomic ops (hw_params,

hw_free and prepare) and the atomic ops aren't perfect; there is a

check of the conflicting PCM state at the beginning of hw_params & co,

but the atomic PCM ops can be still issued during the non-atomic PCM

operations. An example such scenario is that a thread A re-issues the

PREPARE or HW_PARAMS for the already prepared stream, while another

thread B triggers the PCM start in the middle of the prepare

operation. Although this usually doesn't lead to much serious issues,

it can give some inconsistency as reported by syzkaller (such as

ODEBUG warning).

There are various atomic PCM ops, and basically the only problem is

the PCM start as it operates from the PREPARED state. Other trigger

commands (stop, etc) are for the run

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References