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CVE-2026-46157 Linux CVE debrief

A data race vulnerability in the Linux kernel's ALSA PCM OSS (Open Sound System) compatibility layer could allow concurrent, unprotected access to the `runtime.oss.trigger` bit field. Because this field is a bit field, unsynchronized writes risk corrupting adjacent bit fields, leading to undefined behavior and potential operational confusion. The issue was discovered through fuzzing. The fix adds `params_lock` mutex protection around accesses to `runtime.oss.trigger` in both `snd_pcm_oss_get_trigger()` and `snd_pcm_oss_poll()`.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-28
Original CVE updated
2026-05-30
Advisory published
2026-05-28
Advisory updated
2026-05-30

Who should care

Linux system administrators, kernel maintainers, and organizations running workloads with ALSA OSS compatibility enabled, particularly in multi-tenant or high-concurrency audio processing environments

Technical summary

The vulnerability exists in the ALSA (Advanced Linux Sound Architecture) PCM subsystem's OSS compatibility layer. The `runtime.oss.trigger` bit field was accessed without proper synchronization, creating a data race condition. Because bit fields share storage units, concurrent writes to `trigger` could inadvertently modify adjacent bit fields, causing operational confusion. The resolution involves extending the existing `params_lock` mutex coverage to protect read and write operations on `runtime.oss.trigger` in `snd_pcm_oss_get_trigger()` and `snd_pcm_oss_poll()` functions.

Defensive priority

medium

Recommended defensive actions

  • Apply kernel updates containing the referenced stable commits when available for your distribution
  • Monitor vendor security advisories for kernel package updates addressing CVE-2026-46157
  • If running systems with ALSA OSS compatibility enabled, prioritize patching on multi-user or containerized environments where concurrent audio access may occur
  • Review system logs for unexpected ALSA/OSS-related errors that could indicate trigger state corruption

Evidence notes

The CVE description and kernel commit references confirm this is a data race in ALSA PCM OSS code, resolved by adding mutex protection. Multiple stable kernel branch commits are referenced, indicating backports to supported releases.

Official resources

2026-05-28