Linux kernel ALSA pcm use-after-free in snd_pcm_drain()
CVE-2026-43437 Published on May 8, 2026
ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()
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.
Products Associated with CVE-2026-43437
Want to know whenever a new CVE is published for Linux Kernel? stack.watch will email you.
Affected Versions
Linux:- Version f2b3614cefb61ee6046a0aaee503ee37f227d310 and below 9baee36e8c5443411c4629afabafaff8a46a23fd is affected.
- Version f2b3614cefb61ee6046a0aaee503ee37f227d310 and below fc71f888994569f87d5bee20b1ac6c9c1e3a7a79 is affected.
- Version f2b3614cefb61ee6046a0aaee503ee37f227d310 and below 629cf09464cf98670996ea5c191dc9743e6f3f00 is affected.
- Version f2b3614cefb61ee6046a0aaee503ee37f227d310 and below ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432 is affected.
- Version f2b3614cefb61ee6046a0aaee503ee37f227d310 and below 4a758e9a1f5ed722f83c4dd35f867fe811553bcb is affected.
- Version f2b3614cefb61ee6046a0aaee503ee37f227d310 and below c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694 is affected.
- Version f2b3614cefb61ee6046a0aaee503ee37f227d310 and below 9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6 is affected.
- Version 3.0 is affected.
- Before 3.0 is unaffected.
- Version 5.10.253, <= 5.10.* is unaffected.
- Version 6.1.167, <= 6.1.* is unaffected.
- Version 6.6.130, <= 6.6.* is unaffected.
- Version 6.12.78, <= 6.12.* is unaffected.
- Version 6.18.19, <= 6.18.* is unaffected.
- Version 6.19.9, <= 6.19.* is unaffected.
- Version 7.0, <= * is unaffected.