{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2"
            },
            {
              "fixed": "f5d470b808bc01f70978e22e595c6f7768313406"
            },
            {
              "fixed": "936641af564c3d92721704b781e36aaf223efdd2"
            },
            {
              "fixed": "718f6a56b40875f19e6915799044a02df9abfd52"
            },
            {
              "fixed": "11165fe2c5ea0516debe486d91df67abbe36905e"
            },
            {
              "fixed": "d6fd2afb137f52bf00c5210cc44d08ed54dcffb4"
            },
            {
              "fixed": "ef7607ab1c8adc6258fb1b27d08e26aecdc18a58"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.12"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74387.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: midi: Serialize output teardown with event_input\n\nevent_process_midi() borrows msynth-\u003eoutput_rfile.output and then\npasses the substream to dump_midi() and snd_rawmidi_kernel_write()\nwithout synchronizing with the output open/close transition.\nmidisynth_use() also publishes output_rfile before\nsnd_rawmidi_output_params() has finished.\n\nThe last midisynth_unuse() can therefore release the same rawmidi file\nand free substream-\u003eruntime before snd_rawmidi_kernel_write1() takes\nits runtime buffer reference. That leaves the event_input path using a\nstale substream or runtime and can end in a NULL-deref or use-after-free.\n\nFix this with two pieces of synchronization. Keep a short IRQ-safe\nspinlock only for publishing or clearing output_rfile and for pairing\nthe output snapshot with an snd_use_lock_t reference. Once\nevent_process_midi() has taken that in-flight reference, it drops the\nspinlock before calling snd_seq_dump_var_event(), dump_midi(), or\nsnd_rawmidi_kernel_write(). midisynth_unuse() now detaches the visible\nrawmidi file under the same spinlock, waits for the in-flight writers\nto drain, and only then drains and releases the saved file.\nmidisynth_use() likewise opens into a local snd_rawmidi_file and\npublishes it only after snd_rawmidi_output_params() succeeds.\n\nThe buggy scenario involves two paths, with each column showing the\norder within that path:\n\nevent_input path:                     last unuse path:\n1. event_process_midi() snapshots    1. midisynth_unuse() starts\n   output_rfile.output.                 tearing down output_rfile.\n2. dump_midi() reaches               2. snd_rawmidi_kernel_release()\n   snd_rawmidi_kernel_write()           closes the output file.\n   before runtime is pinned.         3. close_substream() frees\n3. The callback keeps using             substream-\u003eruntime.\n   the borrowed substream.\n\nValidation reproduced this kernel report:\nKASAN null-ptr-deref in snd_rawmidi_kernel_write1+0x56/0x360\nRIP: 0033:0x7fde7dd0837f\nRIP: 0010:snd_rawmidi_kernel_write1+0x56/0x360",
  "id": "CVE-2026-74387",
  "modified": "2026-08-16T03:30:59.188079770Z",
  "published": "2026-08-15T05:59:02.457Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/11165fe2c5ea0516debe486d91df67abbe36905e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/718f6a56b40875f19e6915799044a02df9abfd52"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/936641af564c3d92721704b781e36aaf223efdd2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d6fd2afb137f52bf00c5210cc44d08ed54dcffb4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ef7607ab1c8adc6258fb1b27d08e26aecdc18a58"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f5d470b808bc01f70978e22e595c6f7768313406"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74387.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74387"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "ALSA: seq: midi: Serialize output teardown with event_input"
}