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CVE-2026-43437

ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.253, 5.15.220, 6.1.167, 6.6.130, 6.12.78, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From f2b3614cefb61ee6046a0aaee503ee37f227d310 · fixed in 9baee36e8c5443411c4629afabafaff8a46a23fd; From f2b3614cefb61ee6046a0aaee503ee37f227d310 · fixed in f2cb2e0d27fb925c73a78f0ce7d6dbf68d3747c1; From f2b3614cefb61ee6046a0aaee503ee37f227d310 · fixed in fc71f888994569f87d5bee20b1ac6c9c1e3a7a79; From f2b3614cefb61ee6046a0aaee503ee37f227d310 · fixed in 629cf09464cf98670996ea5c191dc9743e6f3f00; From f2b3614cefb61ee6046a0aaee503ee37f227d310 · fixed in ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432; From f2b3614cefb61ee6046a0aaee503ee37f227d310 · fixed in 4a758e9a1f5ed722f83c4dd35f867fe811553bcb; From f2b3614cefb61ee6046a0aaee503ee37f227d310 · fixed in c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694; From f2b3614cefb61ee6046a0aaee503ee37f227d310 · fixed in 9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6

  • Linux Linux

    3.0

  • KernelLinux

    From 3.0.0 · fixed in 5.10.253; From 5.11.0 · fixed in 5.15.220; From 5.16.0 · fixed in 6.1.167; From 6.2.0 · fixed in 6.6.130; From 6.7.0 · fixed in 6.12.78; From 6.13.0 · fixed in 6.18.19; From 6.19.0 · fixed in 6.19.9

References 8

git.kernel.org