ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()_CVE-2026-43437

{
    "lastseen": "",
    "description": "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 'runtime' is reassigned to a\nlinked stream's runtime (runtime = s->runtime at line 2157).  After\nreleasing the stream lock at line 2169, the code accesses\nruntime->no_period_wakeup, runtime->rate, and runtime->buffer_size\n(lines 2170-2178) \u2014 all referencing the linked stream's runtime without\nany lock or refcount protecting its lifetime.\n\nA concurrent close() on the linked stream's 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.",
    "published": "2026-05-08T14:22:07.314Z",
    "modified": "2026-05-11T06:34:28.055Z",
    "type": "cve",
    "title": "ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/9baee36e8c5443411c4629afabafaff8a46a23fd\nhttps://git.kernel.org/stable/c/fc71f888994569f87d5bee20b1ac6c9c1e3a7a79\nhttps://git.kernel.org/stable/c/629cf09464cf98670996ea5c191dc9743e6f3f00\nhttps://git.kernel.org/stable/c/ae8f8d30d334bad5b1b3cdb1eb8a0b771f55e432\nhttps://git.kernel.org/stable/c/4a758e9a1f5ed722f83c4dd35f867fe811553bcb\nhttps://git.kernel.org/stable/c/c2f64e05a0587a83ec42dbd6b7a7ded79b2ff694\nhttps://git.kernel.org/stable/c/9b1dbd69ba6f8f8c69bc7b77c2ce3b9c6ed05ba6",
    "id": "CVE-2026-43437",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux f2b3614cefb61ee6046a0aaee503ee37f227d310\nLinux Linux f2b3614cefb61ee6046a0aaee503ee37f227d310\nLinux Linux f2b3614cefb61ee6046a0aaee503ee37f227d310\nLinux Linux f2b3614cefb61ee6046a0aaee503ee37f227d310\nLinux Linux f2b3614cefb61ee6046a0aaee503ee37f227d310\nLinux Linux f2b3614cefb61ee6046a0aaee503ee37f227d310\nLinux Linux f2b3614cefb61ee6046a0aaee503ee37f227d310\nLinux Linux 3.0",
    "sourceHref": "",
    "cvss": {
        "score": 7.8,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
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        "baseScore": 0,
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        "confidentialityImpact": "",
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        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "f2b3614cefb61ee6046a0aaee503ee37f227d310",
    "vendor": "Linux",
    "ai_description": "",
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    "ai_score": 0
}