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

Vulnerability from cvelistv5 – Published: 2026-08-06 07:06 – Updated: 2026-08-08 15:13
VLAI
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
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
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)
Create a notification for this product.
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)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_midi.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "380b4bef46c2eb260c7a9c6bb2c5be33ce5a38f9",
              "status": "affected",
              "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4",
              "versionType": "git"
            },
            {
              "lessThan": "87bc316dd6fc90072297c635e10b9aa6075ecda1",
              "status": "affected",
              "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4",
              "versionType": "git"
            },
            {
              "lessThan": "f45089eaad0a083d71d84ff175741d7e157d9b69",
              "status": "affected",
              "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4",
              "versionType": "git"
            },
            {
              "lessThan": "ac9a51d910bb7465c554c45320cb6c09f3d0b49d",
              "status": "affected",
              "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4",
              "versionType": "git"
            },
            {
              "lessThan": "5650c18d93a1db7e27cb5a40b394747eb4686d5b",
              "status": "affected",
              "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "89019ab7a64fcdf98a2ba7799e5c6aff58d4a05d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3635523e9b96213969693c320302d536774d8e9b",
              "versionType": "git"
            },
            {
              "lessThan": "5.5",
              "status": "affected",
              "version": "5.4.291",
              "versionType": "semver"
            },
            {
              "lessThan": "5.11",
              "status": "affected",
              "version": "5.10.235",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_midi.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "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:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.148",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.101",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2-rc5",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.4.291",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.10.235",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "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 by local configfs UDC clear or function unlink (unregister_gadget \u2192 f_midi_unbind/disable) plus ALSA rawmidi write/close on /dev/snd/midi*; no USB host traffic or cable access is required, and dummy_hcd suffices, matching other gadget teardown UAFs scored AV:L.\nAC:L - The attacker controls both sides of the race: opening/writing the rawmidi substream to queue midi-\u003ework via f_midi_in_trigger after disable, and forcing unbind plus dropping the last free_ref via configfs unlink/close, so the window is freely repeatable.\nPR:L - Exploitation needs access to the gadget configfs tree and/or the ALSA MIDI node; both are routinely delegated to non-root system/audio accounts on Android and embedded MIDI gadgets, with no capability check on the rawmidi write or UDC store path itself.\nUI:N - The attacker performs the full sequence\u2014configfs unbind/unlink, rawmidi write to rearm work, and close to free the midi object\u2014without any action by another user or administrator.\nS:U - The use-after-free corrupts kernel heap within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - f_midi_in_work() container_of()s the freed embedded work_struct and then reads midi-\u003ein_ep, fifo, and port/substream fields; reclaiming the freed f_midi slab yields a classic UAF read/disclosure primitive.\nI:H - Post-free f_midi_transmit()/f_midi_drop_out_substreams() write through the reclaimed object (port state, kfifo, snd_rawmidi_drop_output), giving a heap write-after-free primitive suitable for control-flow hijack.\nA:H - Dereferencing the freed f_midi from system_highpri_wq reliably produces KASAN reports, oops, or kernel panic even without full exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-08T15:13:21.611Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/380b4bef46c2eb260c7a9c6bb2c5be33ce5a38f9"
        },
        {
          "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"
      }
    }
  },
  "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": "2026-08-08T15:13:21.611Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-64584",
      "date": "2026-08-08",
      "epss": "0.00156",
      "percentile": "0.05252"
    }
  }
}



Log in or create an account to share your comment.




Tags
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.


Detection rules are retrieved from Rulezet.