CVE-2026-43437 (GCVE-0-2026-43437)
Vulnerability from cvelistv5
Published
2026-05-08 14:22
Modified
2026-05-11 22:24
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: f2b3614cefb61ee6046a0aaee503ee37f227d310
Version: f2b3614cefb61ee6046a0aaee503ee37f227d310
Version: f2b3614cefb61ee6046a0aaee503ee37f227d310
Version: f2b3614cefb61ee6046a0aaee503ee37f227d310
Version: f2b3614cefb61ee6046a0aaee503ee37f227d310
Version: f2b3614cefb61ee6046a0aaee503ee37f227d310
Version: f2b3614cefb61ee6046a0aaee503ee37f227d310
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      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()\n\nIn the drain loop, the local variable \u0027runtime\u0027 is reassigned to a\nlinked stream\u0027s runtime (runtime = s-\u003eruntime at line 2157).  After\nreleasing the stream lock at line 2169, the code accesses\nruntime-\u003eno_period_wakeup, runtime-\u003erate, and runtime-\u003ebuffer_size\n(lines 2170-2178) \u2014 all referencing the linked stream\u0027s runtime without\nany lock or refcount protecting its lifetime.\n\nA concurrent close() on the linked stream\u0027s fd triggers\nsnd_pcm_release_substream() \u2192 snd_pcm_drop() \u2192 pcm_release_private()\n\u2192 snd_pcm_unlink() \u2192 snd_pcm_detach_substream() \u2192 kfree(runtime).\nNo synchronization prevents kfree(runtime) from completing while the\ndrain path dereferences the stale pointer.\n\nFix by caching the needed runtime fields (no_period_wakeup, rate,\nbuffer_size) into local variables while still holding the stream lock,\nand using the cached values after the lock is released."
        }
      ],
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
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      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:24:34.477Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/9baee36e8c5443411c4629afabafaff8a46a23fd"
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        {
          "url": "https://git.kernel.org/stable/c/fc71f888994569f87d5bee20b1ac6c9c1e3a7a79"
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          "url": "https://git.kernel.org/stable/c/629cf09464cf98670996ea5c191dc9743e6f3f00"
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        },
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          "url": "https://git.kernel.org/stable/c/9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6"
        }
      ],
      "title": "ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43437",
    "datePublished": "2026-05-08T14:22:07.314Z",
    "dateReserved": "2026-05-01T14:12:56.009Z",
    "dateUpdated": "2026-05-11T22:24:34.477Z",
    "state": "PUBLISHED"
  },
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}


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