ALSA: usb-audio: fix use-after-free in ump_to_endpoint()

{
  "id": "1538d8c93d8f3fa4e989587d41a3ef972ac08535a588ecc995486b24c4b3c825",
  "url": "https://osv.dev/vulnerability/CVE-2026-74501",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ALSA: usb-audio: fix use-after-free in ump_to_endpoint()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: fix use-after-free in ump_to_endpoint() create_midi2_ump() registers a card-owned snd_ump_endpoint and stores a back-pointer to its per-interface snd_usb_midi2_ump object in ump->private_data, but it never installs an ump->private_free hook and never clears that pointer. If a later step of snd_usb_midi_v2_create() fails, its error path calls free_all_midi2_umps(), which kfree()s the snd_usb_midi2_ump object while the already-registered endpoint keeps pointing at it. The created /dev/snd/umpC*D* node stays exposed, so the first operation of any UMP open, ump_to_endpoint(), dereferences the dangling ump->private_data and reads rmidi->eps[dir] out of freed memory. A malicious USB MIDI 2.0 device that makes creation fail after the endpoint is registered can thus trigger a slab use-after-free read on a subsequent open of the UMP node. Clear the endpoint's back-pointer before freeing the object, and let ump_to_endpoint() tolerate a NULL private_data so the open/close/trigger callbacks fail cleanly (their callers already handle a NULL endpoint) instead of dereferencing a stale pointer. Discovered by XBOW, triaged by Baul Lee",
    "evidence": "osv:CVE-2026-74501",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.151",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.103",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.44",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-74501",
      "aliases": [
        "CVE-2026-74501"
      ],
      "affected": [
        {
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              "type": "GIT",
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                {
                  "fixed": "49eccef6d6e1c00dac6fb2e7eb6f9206c33e1c37"
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                {
                  "fixed": "8a7a33b846d6ba695891b8d0040027cdbad8cd52"
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                {
                  "fixed": "cc014ebf803174f0e5d15956dfc5a38413c945ae"
                },
                {
                  "fixed": "ae388c0e1bf727972096f770f82d12e4f748d1b6"
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                {
                  "fixed": "4a05b2d1b4642df74f30b6f54843e825c4a2bfd3"
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            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74501.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
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                  "introduced": "6.5.0"
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              "type": "ECOSYSTEM",
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                  "introduced": "6.19.0"
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                {
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74501.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:41.181425837Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/49eccef6d6e1c00dac6fb2e7eb6f9206c33e1c37",
        "https://git.kernel.org/stable/c/4a05b2d1b4642df74f30b6f54843e825c4a2bfd3",
        "https://git.kernel.org/stable/c/8a7a33b846d6ba695891b8d0040027cdbad8cd52",
        "https://git.kernel.org/stable/c/ae388c0e1bf727972096f770f82d12e4f748d1b6",
        "https://git.kernel.org/stable/c/cc014ebf803174f0e5d15956dfc5a38413c945ae",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74501.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-74501",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74501.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-74501",
        "evidence": "/id"
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    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 509103,
  "published_at": "2026-08-15T12:27:26.957+00:00"
}