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ALSA: seq: Serialize UMP output teardown with event_input

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Serialize UMP output teardown with event_input seq_ump_process_event() borrows client->out_rfile.output without synchronizing with the first-open and last-close transition in seq_ump_client_open() and seq_ump_client_close(). The last output unuse can therefore drop opened[STR_OUT] to zero and release the rawmidi file while an in-flight event_input callback is still inside snd_rawmidi_kernel_write(). That leaves the rawmidi substream runtime exposed to teardown before the write path has taken its own buffer reference. Add a per-client rwlock for the event_input-visible output file. Publish a newly opened output file under the write side, and hold the read side from the output lookup through snd_rawmidi_kernel_write(). The last output close copies and clears the visible output file under the write side, then drops the lock and releases the saved rawmidi file. Use IRQ-safe rwlock guards because event_input can also be reached from atomic sequencer delivery. The buggy scenario involves two paths, with each column showing the order within that path: path A label: event_input path path B label: last unuse path 1. seq_ump_process_event() reads 1. seq_ump_client_close() client->out_rfile.output. drops opened[STR_OUT] to zero. 2. snd_rawmidi_kernel_write1() 2. snd_rawmidi_kernel_release() has not yet pinned runtime. closes the output file. 3. The writer continues using 3. close_substream() frees the borrowe

Announced Source revision 1
Original source ↗

CVE-2026-64029

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-64029

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "81fd444aa371261cd33f31d4ffd80faeeeab0cc9",
        "lessThan": "8ba1c4ddbb1c67d34bb440aecb9f5690ed3f64cb",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "81fd444aa371261cd33f31d4ffd80faeeeab0cc9",
        "lessThan": "0cb1ad795570167558530d6194297ac2396a1991",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "81fd444aa371261cd33f31d4ffd80faeeeab0cc9",
        "lessThan": "3aab4a58d23fb22dac5b558bbe5df1a8dad00b4b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "81fd444aa371261cd33f31d4ffd80faeeeab0cc9",
        "lessThan": "ef46b616a4c219185bbf10ebcbacb571583fd0e4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "81fd444aa371261cd33f31d4ffd80faeeeab0cc9",
        "lessThan": "60a1969fae6209644698fca91c185d153674f631",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "sound/core/seq/seq_ump_client.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.5"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.5",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.142",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.92",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.34",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.0.11",
        "versionType": "semver",
        "lessThanOrEqual": "7.0.*"
      },
      {
        "status": "unaffected",
        "version": "7.1",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "sound/core/seq/seq_ump_client.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-64029

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#40939 · Revision 1
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