CVE-2026-43437

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.

• linux linux kernel (>= 3.0 < 5.10.253) • linux linux kernel (>= 5.11 < 6.1.167) • linux linux kernel (>= 6.2 < 6.6.130) • linux linux kernel (>= 6.7 < 6.12.78) • linux linux kernel (>= 6.13 < 6.18.19) • linux linux kernel (>= 6.19 < 6.19.9) • linux linux kernel 7.0