Highly exploitable, CVE-2026-64584 poses a critical security risk that could lead to severe breaches.
Status: Received on 06 Aug 2026, 08:16 UTC
Last updated: 🕔 19 Aug 2026, 17:20 UTC
Originally published on: 🕗 06 Aug 2026, 08:16 UTC
Time between publication and last update: 13 days
CVSS Release: version 3
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Secondary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVE-2026-64584: 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.
The exploitability of CVE-2026-64584 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2026-64584 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-64584, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-64584, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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