In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()
In the drain loop, the local variable 'runtime' is reassigned to a
linked stream's runtime (runtime = s->runtime at line 2157). After
releasing the stream lock at line 2169, the code accesses
runtime->no_period_wakeup, runtime->rate, and runtime->buffer_size
(lines 2170-2178) — all referencing the linked stream's runtime without
any lock or refcount protecting its lifetime.
A concurrent close() on the linked stream's fd triggers
snd_pcm_release_substream() → snd_pcm_drop() → pcm_release_private()
→ snd_pcm_unlink() → snd_pcm_detach_substream() → kfree(runtime).
No synchronization prevents kfree(runtime) from completing while the
drain path dereferences the stale pointer.
Fix by caching the needed runtime fields (no_period_wakeup, rate,
buffer_size) into local variables while still holding the stream lock,
and using the cached values after the lock is released.
References
Configurations
Configuration 1 (hide)
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History
No history.
Information
Published : 2026-05-08 15:16
Updated : 2026-09-02 13:17
NVD link : CVE-2026-43437
Mitre link : CVE-2026-43437
CVE.ORG link : CVE-2026-43437
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-416
Use After Free