Vulnerability-Lookup

GHSA-M3H2-47PX-55RM

Vulnerability from github – Published: 2026-08-06 09:30 – Updated: 2026-08-06 09:30

Details

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: f_midi: cancel pending IN work before freeing the midi object

The f_midi driver embeds a work item (midi->work) whose handler, f_midi_in_work(), dereferences the enclosing struct f_midi through container_of(). This work is armed from two sites: f_midi_complete(), on a normal IN-endpoint completion, and f_midi_in_trigger(), on an ALSA rawmidi output-stream start.

Neither f_midi_disable() nor f_midi_unbind() cancels midi->work. f_midi_disable() only disables the endpoints and drains the in_req_fifo; it does not synchronize the work item, and the sound card is released asynchronously to the final free of the midi object.

The midi object is reference-counted (midi->free_ref) and is freed in f_midi_free() only once both the usb_function reference and the rawmidi private_data reference have been dropped. In f_midi_unbind(), f_midi_disable() runs before the sound card is released, so while the USB endpoints are already disabled the rawmidi device is still usable by an open substream. A concurrent userspace write on such a substream can reach f_midi_in_trigger() and queue midi->work again after f_midi_disable() has returned. A work item armed this way may still be pending when the last reference drops and f_midi_free() proceeds to kfree(midi), letting f_midi_in_work() dereference the struct after it has been freed, a use-after-free.

For this reason cancelling midi->work in f_midi_disable() would not be sufficient: the ALSA trigger path can rearm the work after disable() returns. Cancelling at the refcount-zero free site is the boundary after which neither arming source can survive, because by then both references that keep the midi object alive have been dropped: the USB endpoints are already disabled and the rawmidi device has been released.

Fix this by calling cancel_work_sync(&midi->work) in the refcount-zero block of f_midi_free(), before the embedded work_struct is freed along with the rest of the structure. opts->lock is a sleeping mutex, so calling cancel_work_sync() under it is permitted, and the handler takes midi->transmit_lock rather than opts->lock, so no self-deadlock can occur while it waits for a running instance of the work to finish.

This issue was found by an in-house static analysis tool.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64584"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-06T08:16:33Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_midi: cancel pending IN work before freeing the midi object\n\nThe f_midi driver embeds a work item (midi-\u003ework) whose handler,\nf_midi_in_work(), dereferences the enclosing struct f_midi through\ncontainer_of().  This work is armed from two sites: f_midi_complete(),\non a normal IN-endpoint completion, and f_midi_in_trigger(), on an ALSA\nrawmidi output-stream start.\n\nNeither f_midi_disable() nor f_midi_unbind() cancels midi-\u003ework.\nf_midi_disable() only disables the endpoints and drains the in_req_fifo;\nit does not synchronize the work item, and the sound card is released\nasynchronously to the final free of the midi object.\n\nThe midi object is reference-counted (midi-\u003efree_ref) and is freed in\nf_midi_free() only once both the usb_function reference and the rawmidi\nprivate_data reference have been dropped.  In f_midi_unbind(),\nf_midi_disable() runs before the sound card is released, so while the\nUSB endpoints are already disabled the rawmidi device is still usable by\nan open substream.  A concurrent userspace write on such a substream can\nreach f_midi_in_trigger() and queue midi-\u003ework again after\nf_midi_disable() has returned.  A work item armed this way may still be\npending when the last reference drops and f_midi_free() proceeds to\nkfree(midi), letting f_midi_in_work() dereference the struct after it\nhas been freed, a use-after-free.\n\nFor this reason cancelling midi-\u003ework in f_midi_disable() would not be\nsufficient: the ALSA trigger path can rearm the work after disable()\nreturns.  Cancelling at the refcount-zero free site is the boundary\nafter which neither arming source can survive, because by then both\nreferences that keep the midi object alive have been dropped: the USB\nendpoints are already disabled and the rawmidi device has been released.\n\nFix this by calling cancel_work_sync(\u0026midi-\u003ework) in the refcount-zero\nblock of f_midi_free(), before the embedded work_struct is freed along\nwith the rest of the structure.  opts-\u003elock is a sleeping mutex, so\ncalling cancel_work_sync() under it is permitted, and the handler takes\nmidi-\u003etransmit_lock rather than opts-\u003elock, so no self-deadlock can\noccur while it waits for a running instance of the work to finish.\n\nThis issue was found by an in-house static analysis tool.",
  "id": "GHSA-m3h2-47px-55rm",
  "modified": "2026-08-06T09:30:32Z",
  "published": "2026-08-06T09:30:32Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64584"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/380b4bef46c2eb260c7a9c6bb2c5be33ce5a38f9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5650c18d93a1db7e27cb5a40b394747eb4686d5b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/87bc316dd6fc90072297c635e10b9aa6075ecda1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ac9a51d910bb7465c554c45320cb6c09f3d0b49d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f45089eaad0a083d71d84ff175741d7e157d9b69"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-64584 (GCVE-0-2026-64584)

Vulnerability from cvelistv5 – Published: 2026-08-06 07:06 – Updated: 2026-08-06 07:06

Title

usb: gadget: f_midi: cancel pending IN work before freeing the midi object

Summary

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_midi: cancel pending IN work before freeing the midi object The f_midi driver embeds a work item (midi->work) whose handler, f_midi_in_work(), dereferences the enclosing struct f_midi through container_of(). This work is armed from two sites: f_midi_complete(), on a normal IN-endpoint completion, and f_midi_in_trigger(), on an ALSA rawmidi output-stream start. Neither f_midi_disable() nor f_midi_unbind() cancels midi->work. f_midi_disable() only disables the endpoints and drains the in_req_fifo; it does not synchronize the work item, and the sound card is released asynchronously to the final free of the midi object. The midi object is reference-counted (midi->free_ref) and is freed in f_midi_free() only once both the usb_function reference and the rawmidi private_data reference have been dropped. In f_midi_unbind(), f_midi_disable() runs before the sound card is released, so while the USB endpoints are already disabled the rawmidi device is still usable by an open substream. A concurrent userspace write on such a substream can reach f_midi_in_trigger() and queue midi->work again after f_midi_disable() has returned. A work item armed this way may still be pending when the last reference drops and f_midi_free() proceeds to kfree(midi), letting f_midi_in_work() dereference the struct after it has been freed, a use-after-free. For this reason cancelling midi->work in f_midi_disable() would not be sufficient: the ALSA trigger path can rearm the work after disable() returns. Cancelling at the refcount-zero free site is the boundary after which neither arming source can survive, because by then both references that keep the midi object alive have been dropped: the USB endpoints are already disabled and the rawmidi device has been released. Fix this by calling cancel_work_sync(&midi->work) in the refcount-zero block of f_midi_free(), before the embedded work_struct is freed along with the rest of the structure. opts->lock is a sleeping mutex, so calling cancel_work_sync() under it is permitted, and the handler takes midi->transmit_lock rather than opts->lock, so no self-deadlock can occur while it waits for a running instance of the work to finish. This issue was found by an in-house static analysis tool.

Severity

No CVSS data available.

Assigner

Linux

References

5 references

URL	Tags
https://git.kernel.org/stable/c/380b4bef46c2eb260…
https://git.kernel.org/stable/c/87bc316dd6fc90072…
https://git.kernel.org/stable/c/f45089eaad0a083d7…
https://git.kernel.org/stable/c/ac9a51d910bb7465c…
https://git.kernel.org/stable/c/5650c18d93a1db7e2…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 8653d71ce3763aedcf3d2331f59beda3fecd79e4 , < 380b4bef46c2eb260c7a9c6bb2c5be33ce5a38f9 (git) Affected: 8653d71ce3763aedcf3d2331f59beda3fecd79e4 , < 87bc316dd6fc90072297c635e10b9aa6075ecda1 (git) Affected: 8653d71ce3763aedcf3d2331f59beda3fecd79e4 , < f45089eaad0a083d71d84ff175741d7e157d9b69 (git) Affected: 8653d71ce3763aedcf3d2331f59beda3fecd79e4 , < ac9a51d910bb7465c554c45320cb6c09f3d0b49d (git) Affected: 8653d71ce3763aedcf3d2331f59beda3fecd79e4 , < 5650c18d93a1db7e27cb5a40b394747eb4686d5b (git) Affected: 89019ab7a64fcdf98a2ba7799e5c6aff58d4a05d (git) Affected: 3635523e9b96213969693c320302d536774d8e9b (git) Affected: 5.4.291 , < 5.5 (semver) Affected: 5.10.235 , < 5.11 (semver)
Linux	Linux	Affected: 5.12 Unaffected: 0 , < 5.12 (semver) Unaffected: 6.6.148 , ≤ 6.6.* (semver) Unaffected: 6.12.101 , ≤ 6.12.* (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2-rc5 , ≤ * (original_commit_for_fix)

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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
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            "drivers/usb/gadget/function/f_midi.c"
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              "version": "5.4.291",
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            {
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              "version": "5.12"
            },
            {
              "lessThan": "5.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.148",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_midi: cancel pending IN work before freeing the midi object\n\nThe f_midi driver embeds a work item (midi-\u003ework) whose handler,\nf_midi_in_work(), dereferences the enclosing struct f_midi through\ncontainer_of().  This work is armed from two sites: f_midi_complete(),\non a normal IN-endpoint completion, and f_midi_in_trigger(), on an ALSA\nrawmidi output-stream start.\n\nNeither f_midi_disable() nor f_midi_unbind() cancels midi-\u003ework.\nf_midi_disable() only disables the endpoints and drains the in_req_fifo;\nit does not synchronize the work item, and the sound card is released\nasynchronously to the final free of the midi object.\n\nThe midi object is reference-counted (midi-\u003efree_ref) and is freed in\nf_midi_free() only once both the usb_function reference and the rawmidi\nprivate_data reference have been dropped.  In f_midi_unbind(),\nf_midi_disable() runs before the sound card is released, so while the\nUSB endpoints are already disabled the rawmidi device is still usable by\nan open substream.  A concurrent userspace write on such a substream can\nreach f_midi_in_trigger() and queue midi-\u003ework again after\nf_midi_disable() has returned.  A work item armed this way may still be\npending when the last reference drops and f_midi_free() proceeds to\nkfree(midi), letting f_midi_in_work() dereference the struct after it\nhas been freed, a use-after-free.\n\nFor this reason cancelling midi-\u003ework in f_midi_disable() would not be\nsufficient: the ALSA trigger path can rearm the work after disable()\nreturns.  Cancelling at the refcount-zero free site is the boundary\nafter which neither arming source can survive, because by then both\nreferences that keep the midi object alive have been dropped: the USB\nendpoints are already disabled and the rawmidi device has been released.\n\nFix this by calling cancel_work_sync(\u0026midi-\u003ework) in the refcount-zero\nblock of f_midi_free(), before the embedded work_struct is freed along\nwith the rest of the structure.  opts-\u003elock is a sleeping mutex, so\ncalling cancel_work_sync() under it is permitted, and the handler takes\nmidi-\u003etransmit_lock rather than opts-\u003elock, so no self-deadlock can\noccur while it waits for a running instance of the work to finish.\n\nThis issue was found by an in-house static analysis tool."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-06T07:06:25.953Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/380b4bef46c2eb260c7a9c6bb2c5be33ce5a38f9"
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        {
          "url": "https://git.kernel.org/stable/c/87bc316dd6fc90072297c635e10b9aa6075ecda1"
        },
        {
          "url": "https://git.kernel.org/stable/c/f45089eaad0a083d71d84ff175741d7e157d9b69"
        },
        {
          "url": "https://git.kernel.org/stable/c/ac9a51d910bb7465c554c45320cb6c09f3d0b49d"
        },
        {
          "url": "https://git.kernel.org/stable/c/5650c18d93a1db7e27cb5a40b394747eb4686d5b"
        }
      ],
      "title": "usb: gadget: f_midi: cancel pending IN work before freeing the midi object",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64584",
    "datePublished": "2026-08-06T07:06:25.953Z",
    "dateReserved": "2026-07-19T15:36:31.798Z",
    "dateUpdated": "2026-08-06T07:06:25.953Z",
    "state": "PUBLISHED"
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}

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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

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GHSA-M3H2-47PX-55RM

CVE-2026-64584 (GCVE-0-2026-64584)

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Nomenclature