{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "sound/core/seq/oss/seq_oss_event.c",
            "sound/core/seq/oss/seq_oss_event.h",
            "sound/core/seq/oss/seq_oss_ioctl.c",
            "sound/core/seq/oss/seq_oss_midi.c",
            "sound/core/seq/oss/seq_oss_midi.h",
            "sound/core/seq/oss/seq_oss_rw.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6dc781778b595be94c31395b2cb167f65145d91f",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "7aad70cabd8f34cf11a9593fcd3f2ac3f5496943",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "7c349b4f2a603202fb8c363bd2774a22ac2fddf3",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "sound/core/seq/oss/seq_oss_event.c",
            "sound/core/seq/oss/seq_oss_event.h",
            "sound/core/seq/oss/seq_oss_ioctl.c",
            "sound/core/seq/oss/seq_oss_midi.c",
            "sound/core/seq/oss/seq_oss_midi.h",
            "sound/core/seq/oss/seq_oss_rw.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.12"
            },
            {
              "lessThan": "2.6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: oss: Fix UAF at handling events with embedded SysEx data\n\nThe OSS sequencer processes the input MIDI bytes into a sequencer\nevent to be dispatched later (in snd_seq_oss_midi_putc() called from\nsnd_seq_oss_process_event()).  When it\u0027s a SysEx data, the event\nrecord contains data.ext.ptr pointer to the original SysEx bytes, and\nthe referred data is copied into the pool afterwards at dispatching.\nThe problem is that, if the sequencer port gets closed concurrently\nbefore the dispatch, the OSS sequencer core also releases the\nresources (in snd_seq_oss_midi_check_exit_port()), while the pending\nevent may hold a stale pointer, eventually leading to a UAF at a later\ndispatch.\n\nFortunately, there is already a refcounting mechanism (snd_use_lock_t)\nfor the OSS MIDI device access, and for addressing the issue above, we\njust need to extend the refcount until the event gets dispatched.\n\nThis patch extends snd_seq_oss_process_event() to give back the\nrefcount object, which is in turn released after calling the sequencer\ndispatcher with the given event in the caller side.\n\nAccording to the original report, KASAN report as below:\n\nKASAN slab-use-after-free in snd_seq_event_dup+0x40c/0x470\nRIP: 0033:0x7f2cb66a6340\nRead of size 6\nCall trace:\n  dump_stack_lvl+0x73/0xb0 (?:?)\n  print_report+0xd1/0x650 (?:?)\n  srso_alias_return_thunk+0x5/0xfbef5 (?:?)\n  __virt_addr_valid+0x1a7/0x340 (?:?)\n  kasan_complete_mode_report_info+0x64/0x200 (?:?)\n  kasan_report+0xf7/0x130 (?:?)\n  snd_seq_event_dup+0x40c/0x470 (?:?)\n  kasan_check_range+0x10c/0x1c0 (?:?)\n  __asan_memcpy+0x27/0x70 (?:?)\n  snd_seq_event_dup+0x9/0x470 (?:?)\n  snd_seq_client_enqueue_event+0x139/0x240 (?:?)\n  _raw_spin_unlock_irqrestore+0x4b/0x60 (?:?)\n  snd_seq_kernel_client_enqueue+0x102/0x120 (?:?)\n  snd_seq_oss_write+0x416/0x4e0 (?:?)\n  apparmor_file_permission+0x20/0x30 (?:?)\n  odev_write+0x3b/0x60 (?:?)\n  vfs_write+0x1ce/0x850 (?:?)\n  lock_release+0xc8/0x2a0 (?:?)\n  __kasan_check_write+0x18/0x20 (?:?)\n  __mutex_unlock_slowpath+0x129/0x510 (?:?)\n  ksys_write+0xe1/0x180 (?:?)\n  mutex_unlock+0x16/0x20 (?:?)\n  odev_ioctl+0x65/0xc0 (?:?)\n  __x64_sys_write+0x46/0x60 (?:?)\n  x64_sys_call+0x7d/0x20d0 (?:?)\n  do_syscall_64+0xc1/0x360 (arch/x86/entry/syscall_64.c:87)\n  entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is reached only via local OSS sequencer character devices (/dev/sequencer, /dev/music) through write(2) or SNDCTL_SEQ_OUTOFBAND ioctl into snd_seq_oss_write(); there is no network, Bluetooth, or physical-device input path to this OSS sequencer code.\nAC:L - The attacker controls both sides of the race: one thread streams SysEx MIDI bytes (SEQ_MIDIPUTC) while another concurrently deletes the backing ALSA sequencer port via /dev/snd/seq or triggers PORT_EXIT teardown, and the window is freely repeatable.\nPR:L - Exploitation requires only a local unprivileged account with access to OSS sequencer and ALSA sequencer device nodes, routinely granted via the audio group or seat ACLs on desktop, studio, and kiosk systems; no capability or init-namespace root is checked on this path.\nUI:N - The attacker\u0027s own process(es) perform the SysEx write and concurrent port-close/delete sequence; no separate victim action such as opening files, mounting filesystems, or plugging in hardware is required beyond the attacker\u0027s own device access.\nS:U - The use-after-free corrupts kernel heap memory within the same kernel security authority, enabling local privilege escalation or denial of service, but does not cross a VM, IOMMU, or sandbox security boundary.\nC:H - This is a slab use-after-free where snd_seq_event_dup() memcpy-reads from a freed MIDI coder buffer (KASAN: read of size 6); UAF on kernel heap objects enables controlled reuse and arbitrary kernel memory disclosure via heap grooming.\nI:H - Freed seq_oss_midi/coder objects can be reallocated and corrupted through continued SysEx traffic, providing standard kernel heap overwrite primitives that can be leveraged for arbitrary write and local privilege escalation.\nA:H - The UAF is observed as a KASAN slab-use-after-free during event enqueue and reliably causes kernel oops or panic on the vulnerable path; even without full exploitation, triggering the bug causes high availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:46:37.644Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6dc781778b595be94c31395b2cb167f65145d91f"
        },
        {
          "url": "https://git.kernel.org/stable/c/7aad70cabd8f34cf11a9593fcd3f2ac3f5496943"
        },
        {
          "url": "https://git.kernel.org/stable/c/7c349b4f2a603202fb8c363bd2774a22ac2fddf3"
        }
      ],
      "title": "ALSA: seq: oss: Fix UAF at handling events with embedded SysEx data",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74388",
    "datePublished": "2026-08-15T05:59:03.147Z",
    "dateReserved": "2026-08-15T05:44:03.891Z",
    "dateUpdated": "2026-08-17T05:46:37.644Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}