---
id: CVE-2026-74503
title: 'ALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes

  snd_timer_close_locked() marks an instance with SNDRV_TIMER_IFLG_DEAD
  and returns early when the flag…
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'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 586b219a22b1032b28b8bd356b963276c5e5bf53 <
    bb016091010ec401a06e6bdace0cd944ee03d371
  - >-
    Linux >= f46093dd22969037beb1fce2e043f3236be41c92 <
    a26a2e52736f9e39843ca66a2e1ce6bf1adbcd1e
  - >-
    Linux >= da3039e91d1f835874ed6e9a33ea19ee80c2cb92 <
    0c561fab50991df10b1e4daca25886c34a2a9c07
  - >-
    Linux >= da3039e91d1f835874ed6e9a33ea19ee80c2cb92 <
    c2744d5f3aea474513fd2298daecb94a952ce441
  - Linux 60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f
  - Linux >= 6.12.94 < 6.12.103
  - Linux >= 6.18.36 < 6.18.44
  - Linux >= 7.0.13 < 7.1
  - Linux 7.1
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T18:58:23.278795Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:05:50.728Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74503'
references:
  - url: 'https://git.kernel.org/stable/c/bb016091010ec401a06e6bdace0cd944ee03d371'
  - url: 'https://git.kernel.org/stable/c/a26a2e52736f9e39843ca66a2e1ce6bf1adbcd1e'
  - url: 'https://git.kernel.org/stable/c/0c561fab50991df10b1e4daca25886c34a2a9c07'
  - url: 'https://git.kernel.org/stable/c/c2744d5f3aea474513fd2298daecb94a952ce441'
tags:
  - cve.org
epss: 0.00175
epssPercentile: 0.06541
ingestedAt: '2026-10-16T19:46:24.354Z'
---

## Overview

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

ALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes

snd_timer_close_locked() marks an instance with SNDRV_TIMER_IFLG_DEAD
and returns early when the flag is already set, but the flag is never
cleared again.  A completed close ends in remove_slave_links(), which
leaves timeri->timer NULL, so a second close is already harmless through
the timer == NULL path; the early return can only be reached by an
instance that was opened again in between.  For such an instance the
close unlinks nothing, so snd_timer_instance_free() frees an object that
is still on timer->open_list_head, still on snd_timer_master_list if it
was opened with a slave key, still owns any adopted slaves, and still
holds its timer and module references.

snd_seq_timer_open() reopens an instance exactly like that: it retries
its fallback open on the same object after a failure that has already
run snd_timer_close_locked() internally.  An unprivileged user with
access to /dev/snd/timer and /dev/snd/seq can force that failure, since
snd_timer_check_master() returns -EBUSY when a pending slave matches the
new master's (slave_class, slave_id) key and the target timer has
reached max_instances, and SNDRV_TIMER_IOCTL_SELECT with dev_class =
SNDRV_TIMER_CLASS_SLAVE keeps the caller-supplied dev_sclass, so a
sequencer queue's key can be forged.  The freed instance is afterwards
dereferenced by any further snd_timer_open() on that timer, by
snd_timer_check_slave(), and by /proc/asound/timers, which faults on the
stale ti->owner pointer.

The flag only has to be visible while the close is in progress, which is
all its other users need.  Clear it in remove_slave_links(), under the
same timer->lock that sets it, once the instance is off every list.

## Affected

- `Linux >= 586b219a22b1032b28b8bd356b963276c5e5bf53 < bb016091010ec401a06e6bdace0cd944ee03d371`
- `Linux >= f46093dd22969037beb1fce2e043f3236be41c92 < a26a2e52736f9e39843ca66a2e1ce6bf1adbcd1e`
- `Linux >= da3039e91d1f835874ed6e9a33ea19ee80c2cb92 < 0c561fab50991df10b1e4daca25886c34a2a9c07`
- `Linux >= da3039e91d1f835874ed6e9a33ea19ee80c2cb92 < c2744d5f3aea474513fd2298daecb94a952ce441`
- `Linux 60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f`
- `Linux >= 6.12.94 < 6.12.103`
- `Linux >= 6.18.36 < 6.18.44`
- `Linux >= 7.0.13 < 7.1`
- `Linux 7.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.