---
id: CVE-2026-80628
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ALSA: seq: oss: Serialize readq reset state with q->lock

  snd_seq_oss_readq_clear() resets qlen, head, and tail without
  q->lock even though the normal reader and produc…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ALSA: seq: oss: Serialize readq reset state with q->lock

  snd_seq_oss_readq_clear() resets qlen, head, and tail without
  q->lock even though the normal reader and produc…
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'
published: '2026-08-28'
updated: '2026-08-29'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80628'
references:
  - url: 'https://git.kernel.org/stable/c/287d506d4e0865918cec82bb1361f283a08c979b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/43e10709b1ba288bcbabb9b9cb6e518b2a5d8506'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/49ce92d207820f588b0406add82f053decfbe5d9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00127
epssPercentile: 0.02709
ingestedAt: '2026-08-29T23:43:56.405Z'
---

## Overview

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

ALSA: seq: oss: Serialize readq reset state with q->lock

snd_seq_oss_readq_clear() resets qlen, head, and tail without
q->lock even though the normal reader and producer paths serialize the
same ring state under that spinlock. A reset can therefore race
snd_seq_oss_readq_free() or snd_seq_oss_readq_put_event() and leave
stale records in the queue, drop freshly queued ones, or report the
wrong readiness after wakeup. KCSAN reports a data race between
snd_seq_oss_readq_clear() and snd_seq_oss_readq_free().

Take q->lock while clearing the ring and resetting input_time. Factor
the enqueue logic into a caller-locked helper so
snd_seq_oss_readq_put_timestamp() updates its suppression state under
the same lock instead of racing the reset path.

The buggy scenario involves two paths, with each column showing the
order within that path:

reset path:                      locked readq updater:
1. snd_seq_oss_reset() or        1. A reader or callback producer
   release reaches                  takes q->lock on the same queue.
   snd_seq_oss_readq_clear().
2. snd_seq_oss_readq_clear()     2. The updater tests or modifies
   resets qlen, head, tail,         qlen, head, and tail.
   and input_time.
3. snd_seq_oss_readq_clear()     3. The updater completes its
   wakes sleepers on                read-modify-write sequence.
   q->midi_sleep.
4. Without q->lock, the reset    4. The resulting ring state drives
   can overlap the locked           later reads and readiness.
   update.

KCSAN reports:

BUG: KCSAN: data-race in snd_seq_oss_readq_clear /
snd_seq_oss_readq_free

write to 0xffff8881069fe608 of 4 bytes by task 120516 on cpu 0:
  snd_seq_oss_readq_free+0x6c/0x80
  snd_seq_oss_read+0xcb/0x250
  odev_read+0x38/0x60
  vfs_read+0xff/0x600
  ksys_read+0xb4/0x140
  __x64_sys_read+0x46/0x60
  do_syscall_64+0xbb/0x2f0
  entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881069fe608 of 4 bytes by task 120517 on cpu 1:
  snd_seq_oss_readq_clear+0x1f/0x90
  snd_seq_oss_reset+0xa7/0xf0
  snd_seq_oss_ioctl+0x6f6/0x7e0
  odev_ioctl+0x56/0xc0
  __x64_sys_ioctl+0xd1/0x120
  do_syscall_64+0xbb/0x2f0
  entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000000

## Remediation

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