{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64584", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.798Z", "datePublished": "2026-08-06T07:06:25.953Z", "dateUpdated": "2026-08-19T16:29:12.890Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:29:12.890Z" }, "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->work) 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->work.\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->free_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->work 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->work 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(&midi->work) in the refcount-zero\nblock of f_midi_free(), before the embedded work_struct is freed along\nwith the rest of the structure. opts->lock is a sleeping mutex, so\ncalling cancel_work_sync() under it is permitted, and the handler takes\nmidi->transmit_lock rather than opts->lock, 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": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The UAF is reached by local configfs UDC clear or function unlink (unregister_gadget → 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->work 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—configfs unbind/unlink, rawmidi write to rearm work, and close to free the midi object—without 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->in_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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/usb/gadget/function/f_midi.c" ], "versions": [ { "version": "3635523e9b96213969693c320302d536774d8e9b", "lessThan": "f3c6f2c38062703d3dc7f86958bb0790c6959add", "status": "affected", "versionType": "git" }, { "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4", "lessThan": "df18150126f66817e4d3f79f309e9c92d6ff384e", "status": "affected", "versionType": "git" }, { "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4", "lessThan": "620955b222c47332297d6bf38f78541aa699238a", "status": "affected", "versionType": "git" }, { "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4", "lessThan": "380b4bef46c2eb260c7a9c6bb2c5be33ce5a38f9", "status": "affected", "versionType": "git" }, { "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4", "lessThan": "87bc316dd6fc90072297c635e10b9aa6075ecda1", "status": "affected", "versionType": "git" }, { "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4", "lessThan": "f45089eaad0a083d71d84ff175741d7e157d9b69", "status": "affected", "versionType": "git" }, { "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4", "lessThan": "ac9a51d910bb7465c554c45320cb6c09f3d0b49d", "status": "affected", "versionType": "git" }, { "version": "8653d71ce3763aedcf3d2331f59beda3fecd79e4", "lessThan": "5650c18d93a1db7e27cb5a40b394747eb4686d5b", "status": "affected", "versionType": "git" }, { "version": "89019ab7a64fcdf98a2ba7799e5c6aff58d4a05d", "status": "affected", "versionType": "git" }, { "version": "5.10.235", "lessThan": "5.10.265", "status": "affected", "versionType": "semver" }, { "version": "5.4.291", "lessThan": "5.5", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/usb/gadget/function/f_midi.c" ], "versions": [ { "version": "5.12", "status": "affected" }, { "version": "0", "lessThan": "5.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.265", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.235", "versionEndExcluding": "5.10.265" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12", "versionEndExcluding": "5.15.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.291" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f3c6f2c38062703d3dc7f86958bb0790c6959add" }, { "url": "https://git.kernel.org/stable/c/df18150126f66817e4d3f79f309e9c92d6ff384e" }, { "url": "https://git.kernel.org/stable/c/620955b222c47332297d6bf38f78541aa699238a" }, { "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" } } } }