Bug 2492710 (CVE-2026-53242)

Summary: CVE-2026-53242 kernel: ALSA: PCM: Fix wait queue list corruption in snd_pcm_drain() on linked streams
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Advanced Linux Sound Architecture (ALSA) Pulse-Code Modulation (PCM) component of the Linux kernel. This vulnerability involves a corruption of wait queue lists within the `snd_pcm_drain()` function when processing linked streams. An attacker could exploit this issue to trigger a kernel panic, leading to a Denial of Service (DoS) on the affected system.
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Description OSIDB Bzimport 2026-06-25 10:01:43 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ALSA: PCM: Fix wait queue list corruption in snd_pcm_drain() on linked streams

snd_pcm_drain() uses init_waitqueue_entry which does not clear
entry.prev/next, and add_wait_queue with a conditional
remove_wait_queue that is skipped when to_check is no longer
in the group after concurrent UNLINK.  The orphaned wait entry
remains on the unlinked substream sleep queue.  On the next
drain iteration, add_wait_queue adds the entry to a new queue
while still linked on the old one, corrupting both lists.  A
subsequent wake_up dereferences NULL at the func pointer
(mapped from the spinlock at offset 0 of the misinterpreted
wait_queue_head_t), causing a kernel panic.

Replace init_waitqueue_entry/add_wait_queue/conditional
remove_wait_queue with init_wait_entry/prepare_to_wait/
finish_wait.  init_wait_entry clears prev/next via
INIT_LIST_HEAD on each iteration and sets
autoremove_wake_function which auto-removes the entry on
wake-up.  finish_wait safely handles both the already-removed
and still-queued cases.
Comment 1 Mauro Matteo Cascella 2026-06-26 10:29:52 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062511-CVE-2026-53242-45ab@gregkh/T