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CVE-2026-74501 (GCVE-0-2026-74501)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-17 05:20
VLAI
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 <baul.lee@xbow.com>
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: ff49d1df79aef7580fe3ac99d17c3f886655d080 , < 49eccef6d6e1c00dac6fb2e7eb6f9206c33e1c37 (git)
Affected: ff49d1df79aef7580fe3ac99d17c3f886655d080 , < 8a7a33b846d6ba695891b8d0040027cdbad8cd52 (git)
Affected: ff49d1df79aef7580fe3ac99d17c3f886655d080 , < cc014ebf803174f0e5d15956dfc5a38413c945ae (git)
Affected: ff49d1df79aef7580fe3ac99d17c3f886655d080 , < ae388c0e1bf727972096f770f82d12e4f748d1b6 (git)
Affected: ff49d1df79aef7580fe3ac99d17c3f886655d080 , < 4a05b2d1b4642df74f30b6f54843e825c4a2bfd3 (git)
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Linux Linux Affected: 6.5
Unaffected: 0 , < 6.5 (semver)
Unaffected: 6.6.151 , ≤ 6.6.* (semver)
Unaffected: 6.12.103 , ≤ 6.12.* (semver)
Unaffected: 6.18.44 , ≤ 6.18.* (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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          "programFiles": [
            "sound/usb/midi2.c"
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: usb-audio: fix use-after-free in ump_to_endpoint()\n\ncreate_midi2_ump() registers a card-owned snd_ump_endpoint and stores a\nback-pointer to its per-interface snd_usb_midi2_ump object in\nump-\u003eprivate_data, but it never installs an ump-\u003eprivate_free hook and\nnever clears that pointer.\n\nIf a later step of snd_usb_midi_v2_create() fails, its error path calls\nfree_all_midi2_umps(), which kfree()s the snd_usb_midi2_ump object while\nthe already-registered endpoint keeps pointing at it.  The created\n/dev/snd/umpC*D* node stays exposed, so the first operation of any UMP\nopen, ump_to_endpoint(), dereferences the dangling ump-\u003eprivate_data and\nreads rmidi-\u003eeps[dir] out of freed memory.\n\nA malicious USB MIDI 2.0 device that makes creation fail after the\nendpoint is registered can thus trigger a slab use-after-free read on a\nsubsequent open of the UMP node.\n\nClear the endpoint\u0027s back-pointer before freeing the object, and let\nump_to_endpoint() tolerate a NULL private_data so the open/close/trigger\ncallbacks fail cleanly (their callers already handle a NULL endpoint)\ninstead of dereferencing a stale pointer.\n\nDiscovered by XBOW, triaged by Baul Lee \u003cbaul.lee@xbow.com\u003e"
        }
      ],
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        "dateUpdated": "2026-08-17T05:20:39.729Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/49eccef6d6e1c00dac6fb2e7eb6f9206c33e1c37"
        },
        {
          "url": "https://git.kernel.org/stable/c/8a7a33b846d6ba695891b8d0040027cdbad8cd52"
        },
        {
          "url": "https://git.kernel.org/stable/c/cc014ebf803174f0e5d15956dfc5a38413c945ae"
        },
        {
          "url": "https://git.kernel.org/stable/c/ae388c0e1bf727972096f770f82d12e4f748d1b6"
        },
        {
          "url": "https://git.kernel.org/stable/c/4a05b2d1b4642df74f30b6f54843e825c4a2bfd3"
        }
      ],
      "title": "ALSA: usb-audio: fix use-after-free in ump_to_endpoint()",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74501",
    "datePublished": "2026-08-15T12:27:26.957Z",
    "dateReserved": "2026-08-15T05:44:03.907Z",
    "dateUpdated": "2026-08-17T05:20:39.729Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-04",
      "epss": "0.00168",
      "percentile": "0.06318"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T17:40:24+00:00",
      "cve": "CVE-2026-74501",
      "id": "CVE-2026-74501",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ALSA: usb-audio: fix use-after-free in ump_to_endpoint()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74501.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.