CVE-2026-43437
Description
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | fixed | 6.1.170-1 |
| debian | bullseye | fixed | 5.10.257-1 |
| debian | forky | fixed | 6.19.10-1 |
| debian | sid | fixed | 6.19.10-1 |
| debian | trixie | fixed | 6.12.85-1 |
| linux-kernel | affected | 5.10.253 | |
| linux-kernel | 7.0 | affected | |
References
- https://git.kernel.org/stable/c/4a758e9a1f5ed722f83c4dd35f867fe811553bcb
- https://git.kernel.org/stable/c/629cf09464cf98670996ea5c191dc9743e6f3f00
- https://git.kernel.org/stable/c/9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6
- https://git.kernel.org/stable/c/9baee36e8c5443411c4629afabafaff8a46a23fd
- https://git.kernel.org/stable/c/ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432
- https://git.kernel.org/stable/c/c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694
- https://git.kernel.org/stable/c/fc71f888994569f87d5bee20b1ac6c9c1e3a7a79
- https://www.suse.com/security/cve/CVE-2026-43437.html
- https://security-tracker.debian.org/tracker/CVE-2026-43437
CWEs
CWE-416
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.