CVE-2026-74261

Technical Description

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

ALSA: seq: avoid stale FIFO cells during resize

snd_seq_fifo_resize() still needs to publish the replacement pool

before it waits for FIFO users. A blocking snd_seq_read() holds

f->use_lock while it sleeps, so concurrent senders must be able to

queue to the new pool and wake that reader instead of failing against a

closing old pool.

However, snd_seq_fifo_event_in() duplicates an event before it takes

f->lock, and snd_seq_read() can dequeue a cell and later call

snd_seq_fifo_cell_putback() if copy_to_user() or

snd_seq_expand_var_event() fails. If resize swaps f->pool and detaches

oldhead in between, either path can relink an old-pool cell after the

snapshot. That stale cell sits outside the drained oldhead list, keeps

oldpool->counter elevated, and can leave snd_seq_pool_delete() waiting

for the retired pool to drain.

Keep the existing swap-before-wait ordering in snd_seq_fifo_resize(),

but reject stale cells before

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References