CVE-2022-49291: ALSA: pcm: Fix races among concurrent hw_params and hw_free calls

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-26 · updated 2026-06-17
Weakness: CWE-416

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.

Affected products

Linux kernel: before 4.14.279; from 4.15 before 4.19.243; from 4.20 before 5.4.193; from 5.5 before 5.10.109; from 5.11 before 5.15.32; from 5.16 before 5.16.18 — fixed in 4.14.279, 4.19.243, 5.10.109, 5.15.32, 5.16.18, 5.17.1

How to fix

Upgrade to a fixed version: Linux kernel 4.14.279, 4.19.243, 5.10.109, 5.15.32. Check the vendor advisory for mitigations.

References

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