FKIE_CVE-2026-74501

Vulnerability from fkie_nvd - Published: 2026-08-15 13:17 - Updated: 2026-08-17 06:19
Severity
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>
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/49eccef6d6e1c00dac6fb2e7eb6f9206c33e1c37
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4a05b2d1b4642df74f30b6f54843e825c4a2bfd3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8a7a33b846d6ba695891b8d0040027cdbad8cd52
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ae388c0e1bf727972096f770f82d12e4f748d1b6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cc014ebf803174f0e5d15956dfc5a38413c945ae
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "sound/usb/midi2.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "49eccef6d6e1c00dac6fb2e7eb6f9206c33e1c37",
              "status": "affected",
              "version": "ff49d1df79aef7580fe3ac99d17c3f886655d080",
              "versionType": "git"
            },
            {
              "lessThan": "8a7a33b846d6ba695891b8d0040027cdbad8cd52",
              "status": "affected",
              "version": "ff49d1df79aef7580fe3ac99d17c3f886655d080",
              "versionType": "git"
            },
            {
              "lessThan": "cc014ebf803174f0e5d15956dfc5a38413c945ae",
              "status": "affected",
              "version": "ff49d1df79aef7580fe3ac99d17c3f886655d080",
              "versionType": "git"
            },
            {
              "lessThan": "ae388c0e1bf727972096f770f82d12e4f748d1b6",
              "status": "affected",
              "version": "ff49d1df79aef7580fe3ac99d17c3f886655d080",
              "versionType": "git"
            },
            {
              "lessThan": "4a05b2d1b4642df74f30b6f54843e825c4a2bfd3",
              "status": "affected",
              "version": "ff49d1df79aef7580fe3ac99d17c3f886655d080",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "sound/usb/midi2.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.5"
            },
            {
              "lessThan": "6.5",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.151",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.103",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "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"
    }
  ],
  "id": "CVE-2026-74501",
  "lastModified": "2026-08-17T06:19:46.547",
  "metrics": {},
  "published": "2026-08-15T13:17:55.093",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/49eccef6d6e1c00dac6fb2e7eb6f9206c33e1c37"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4a05b2d1b4642df74f30b6f54843e825c4a2bfd3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8a7a33b846d6ba695891b8d0040027cdbad8cd52"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ae388c0e1bf727972096f770f82d12e4f748d1b6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cc014ebf803174f0e5d15956dfc5a38413c945ae"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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