CVE-2026-90207 (GCVE-0-2026-90207)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:07 – Updated: 2026-09-18 17:53
VLAI
Title
ALSA: seq: midi: Serialize input teardown with event_input
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: midi: Serialize input teardown with event_input snd_midi_input_event() must not be running while a rawmidi substream is closing, since this can lead to the trigger state becoming out-of-step through this sequence in snd_rawmidi_input_trigger(): snd_rawmidi_input_trigger(up=0) snd_midi_input_event() -> snd_rawmidi_kernel_read() -> snd_rawmidi_input_trigger(up=1) -> cancel_work_sync() which ends with the underlying device being active unexpectedly. When this is called from close_substream(), further input can re-trigger the input event leaving it running after rawmidi_release_priv() has set rfile->rmidi to NULL which leads to: Unable to handle kernel NULL pointer dereference at virtual address 00000000000000b0 Call trace: snd_midi_input_event+0x3c/0x134 [snd_seq_midi] (P) snd_rawmidi_input_event_work+0x1c/0x2c process_one_work+0x150/0x3a4 worker_thread+0x190/0x318 Apply a similar approach to commit ef7607ab1c8ad ("ALSA: seq: midi: Serialize output teardown with event_input") which fixed the same issue in the output direction, but updated to use RCU following Takashi Iwai's proposed follow-on patch [1]. With this change in place, midisynth_unsubscribe() clears the input file so snd_midi_input_event() will not re-trigger the stream and will be quiesced by the cancel_work_sync() in snd_rawmidi_input_trigger(). [1] https://lore.kernel.org/linux-sound/20260813144224.753399-1-tiwai@suse.de/
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < de76a2b47582cd6dba2e15f024681bf377ecc94a (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 89d986897aff7275b42e075e556731b8353366af (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 6290afaae54c7a9fa3bca3b4d5433e6d83e8669d (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 210c193a9ef1312fab153948c6928e4cfaa1f03b (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 282a3ef9e4b63b2f6823bbbb3c1a90b002cdaf12 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 403f7f3ad3808a0096d84cf228fab68dc253fd9d (git)
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Linux Linux Affected: 2.6.12
Unaffected: 0 , < 2.6.12 (semver)
Unaffected: 6.1.188 , ≤ 6.1.* (semver)
Unaffected: 6.6.157 , ≤ 6.6.* (semver)
Unaffected: 6.12.110 , ≤ 6.12.* (semver)
Unaffected: 6.18.52 , ≤ 6.18.* (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: midi: Serialize input teardown with event_input\n\nsnd_midi_input_event() must not be running while a rawmidi substream is\nclosing, since this can lead to the trigger state becoming out-of-step\nthrough this sequence in snd_rawmidi_input_trigger():\n\n\tsnd_rawmidi_input_trigger(up=0)\n\t\t\t\t\tsnd_midi_input_event()\n\t\t\t\t\t -\u003e snd_rawmidi_kernel_read()\n\t\t\t\t\t     -\u003e snd_rawmidi_input_trigger(up=1)\n\t  -\u003e cancel_work_sync()\n\nwhich ends with the underlying device being active unexpectedly.\n\nWhen this is called from close_substream(), further input can re-trigger\nthe input event leaving it running after rawmidi_release_priv() has set\nrfile-\u003ermidi to NULL which leads to:\n\n\tUnable to handle kernel NULL pointer dereference at virtual address 00000000000000b0\n\tCall trace:\n\t snd_midi_input_event+0x3c/0x134 [snd_seq_midi] (P)\n\t snd_rawmidi_input_event_work+0x1c/0x2c\n\t process_one_work+0x150/0x3a4\n\t worker_thread+0x190/0x318\n\nApply a similar approach to commit ef7607ab1c8ad (\"ALSA: seq: midi:\nSerialize output teardown with event_input\") which fixed the same issue\nin the output direction, but updated to use RCU following Takashi Iwai\u0027s\nproposed follow-on patch [1].\n\nWith this change in place, midisynth_unsubscribe() clears the input file\nso snd_midi_input_event() will not re-trigger the stream and will be\nquiesced by the cancel_work_sync() in snd_rawmidi_input_trigger().\n\n[1] https://lore.kernel.org/linux-sound/20260813144224.753399-1-tiwai@suse.de/"
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            "version": "3.1"
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              "value": "AV:L - The race is reached from a local sequencer client: snd_seq_open() on /dev/snd/seq, SNDRV_SEQ_IOCTL_SUBSCRIBE_PORT (midisynth_subscribe) to open the rawmidi input, then SNDRV_SEQ_IOCTL_UNSUBSCRIBE_PORT or client close (midisynth_unsubscribe -\u003e snd_rawmidi_kernel_release). Bytes that schedule snd_midi_input_event come from the bound rawmidi device, not a network or radio protocol.\nAC:L - The attacker owns teardown (last unsubscribe/close) and starts input by subscribing: midisynth_subscribe sets runtime-\u003eevent to snd_midi_input_event and snd_rawmidi_kernel_read() triggers the device. Concurrent snd_midi_input_event can re-call snd_rawmidi_input_trigger(up=1) during close_substream\u0027s trigger(up=0)/cancel_work_sync window. Repeating subscribe/unsubscribe on that live port makes the race retryable.\nPR:L - snd_seq_open() has no capable() check. check_subscription_permission() allows any sequencer client to subscribe to seq_midi ports because they advertise SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ. Typical DAC on /dev/snd/seq is audio-group/uaccess, so an unprivileged local user suffices; init-namespace root is not required.\nUI:N - The attacker opens their own /dev/snd/seq client, creates a destination port, issues SNDRV_SEQ_IOCTL_SUBSCRIBE_PORT to a seq_midi input port, and then unsubscribes or closes to run midisynth_unsubscribe. No other user must mount, click, or open a file.\nS:U - The UAF/NULL deref is in kernel rawmidi lifetime (close_substream/snd_rawmidi_runtime_free versus snd_rawmidi_input_event_work calling snd_midi_input_event). That is local kernel memory corruption in the same OS authority, not a VM, IOMMU, or sandbox escape.\nC:H - After cancel_work_sync, a re-triggered device can schedule runtime-\u003eevent_work; close_substream then kfree()s snd_rawmidi_runtime while the work later does container_of() and calls runtime-\u003eevent. Use-after-free of that heap object enables arbitrary reads via heap reuse of the freed runtime.\nI:H - The freed snd_rawmidi_runtime embeds event_work and the runtime-\u003eevent function pointer that snd_rawmidi_input_event_work invokes. Heap spraying that object lets an attacker hijack the callback for arbitrary kernel write or control-flow hijack, not merely a one-shot crash.\nA:H - The reported crash is a NULL deref in snd_midi_input_event from snd_rawmidi_input_event_work after rawmidi_release_priv() nulls the file and close_substream frees runtime, which oopses the kernel and can be retried with subscribe/unsubscribe cycles."
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          "url": "https://git.kernel.org/stable/c/403f7f3ad3808a0096d84cf228fab68dc253fd9d"
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    "datePublished": "2026-09-17T16:07:22.825Z",
    "dateReserved": "2026-09-11T19:38:34.793Z",
    "dateUpdated": "2026-09-18T17:53:45.440Z",
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            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: midi: Serialize input teardown with event_input\n\nsnd_midi_input_event() must not be running while a rawmidi substream is\nclosing, since this can lead to the trigger state becoming out-of-step\nthrough this sequence in snd_rawmidi_input_trigger():\n\n\tsnd_rawmidi_input_trigger(up=0)\n\t\t\t\t\tsnd_midi_input_event()\n\t\t\t\t\t -\u003e snd_rawmidi_kernel_read()\n\t\t\t\t\t     -\u003e snd_rawmidi_input_trigger(up=1)\n\t  -\u003e cancel_work_sync()\n\nwhich ends with the underlying device being active unexpectedly.\n\nWhen this is called from close_substream(), further input can re-trigger\nthe input event leaving it running after rawmidi_release_priv() has set\nrfile-\u003ermidi to NULL which leads to:\n\n\tUnable to handle kernel NULL pointer dereference at virtual address 00000000000000b0\n\tCall trace:\n\t snd_midi_input_event+0x3c/0x134 [snd_seq_midi] (P)\n\t snd_rawmidi_input_event_work+0x1c/0x2c\n\t process_one_work+0x150/0x3a4\n\t worker_thread+0x190/0x318\n\nApply a similar approach to commit ef7607ab1c8ad (\"ALSA: seq: midi:\nSerialize output teardown with event_input\") which fixed the same issue\nin the output direction, but updated to use RCU following Takashi Iwai\u0027s\nproposed follow-on patch [1].\n\nWith this change in place, midisynth_unsubscribe() clears the input file\nso snd_midi_input_event() will not re-trigger the stream and will be\nquiesced by the cancel_work_sync() in snd_rawmidi_input_trigger().\n\n[1] https://lore.kernel.org/linux-sound/20260813144224.753399-1-tiwai@suse.de/"
          }
        ],
        "id": "CVE-2026-90207",
        "lastModified": "2026-09-18T18:17:46.560",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-09-17T17:17:15.813",
        "references": [
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            "url": "https://git.kernel.org/stable/c/210c193a9ef1312fab153948c6928e4cfaa1f03b"
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            "url": "https://git.kernel.org/stable/c/89d986897aff7275b42e075e556731b8353366af"
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
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    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-22T16:29:53Z",
      "cve": "CVE-2026-90207",
      "id": "CVE-2026-90207",
      "initial_release_date": "2026-09-18T00:19:56Z",
      "product_status:known_affected": "269",
      "product_status:known_not_affected": "78",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-90207",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-90207.json",
      "version": "4"
    }
  }
}



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Taxonomy of the tags.





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.

Sightings

Author Source Type Date Other

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.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • 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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.