CVE-2026-80628

Status: UPDATED  |  Advisory ID: CVE-2026-80628

Key Details

Affected Products, Subsystems & Sectors

What to Know

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 (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References