---
id: CVE-2026-43437
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()

  In the drain loop, the local variable 'runtime' is reassigned to a
  linked stream's runtime (r…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()

  In the drain loop, the local variable 'runtime' is reassigned to a
  linked stream's runtime (r…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-416
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 3.0, < 5.10.253'
  - 'linux_kernel >= 5.11, < 6.1.167'
  - 'linux_kernel >= 6.2, < 6.6.130'
  - 'linux_kernel >= 6.7, < 6.12.78'
  - 'linux_kernel >= 6.13, < 6.18.19'
  - 'linux_kernel >= 6.19, < 6.19.9'
  - linux_kernel = 7.0
patched:
  - linux_kernel 6.19.9
published: '2026-05-08'
updated: '2026-09-02'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-43437'
references:
  - url: 'https://git.kernel.org/stable/c/4a758e9a1f5ed722f83c4dd35f867fe811553bcb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/629cf09464cf98670996ea5c191dc9743e6f3f00'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9baee36e8c5443411c4629afabafaff8a46a23fd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f2cb2e0d27fb925c73a78f0ce7d6dbf68d3747c1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fc71f888994569f87d5bee20b1ac6c9c1e3a7a79'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00171
epssPercentile: 0.0571
ingestedAt: '2026-09-02T13:44:42.038Z'
---

## Overview

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

ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()

In the drain loop, the local variable 'runtime' is reassigned to a
linked stream's runtime (runtime = s->runtime at line 2157).  After
releasing the stream lock at line 2169, the code accesses
runtime->no_period_wakeup, runtime->rate, and runtime->buffer_size
(lines 2170-2178) — all referencing the linked stream's runtime without
any lock or refcount protecting its lifetime.

A concurrent close() on the linked stream's fd triggers
snd_pcm_release_substream() → snd_pcm_drop() → pcm_release_private()
→ snd_pcm_unlink() → snd_pcm_detach_substream() → kfree(runtime).
No synchronization prevents kfree(runtime) from completing while the
drain path dereferences the stale pointer.

Fix by caching the needed runtime fields (no_period_wakeup, rate,
buffer_size) into local variables while still holding the stream lock,
and using the cached values after the lock is released.

## Affected

- `linux_kernel >= 3.0, < 5.10.253`
- `linux_kernel >= 5.11, < 6.1.167`
- `linux_kernel >= 6.2, < 6.6.130`
- `linux_kernel >= 6.7, < 6.12.78`
- `linux_kernel >= 6.13, < 6.18.19`
- `linux_kernel >= 6.19, < 6.19.9`
- `linux_kernel = 7.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.19.9`