wifi: rtl8xxxu: fix use-after-free from rx_urb_wq on stop

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-80947
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-11 20:19:00 UTC
Updated2026-09-13 07:17:01 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: wifi: rtl8xxxu: fix use-after-free from rx_urb_wq on stop rtl8xxxu arms rx_urb_wq from the RX completion path: rtl8xxxu_rx_complete() hands the URB to rtl8xxxu_queue_rx_urb(), which queues it on rx_urb_pending_list and, once the list grows past RTL8XXXU_RX_URB_PENDING_WATER, schedules rx_urb_wq. The worker rtl8xxxu_rx_urb_work() drains rx_urb_pending_list, recovers priv through container_of, and resubmits each URB through rtl8xxxu_submit_rx_urb(), which anchors it on rx_anchor and dereferences priv->udev. rtl8xxxu_stop() cancels the sibling work items (c2hcmd_work, ra_watchdog, update_beacon_work) but never cancels rx_urb_wq, so a worker armed during the last burst of RX traffic can run rtl8xxxu_rx_urb_work() after rtl8xxxu_disconnect() has called ieee80211_free_hw(), which frees priv, producing a use-after-free. The window opens under active RX traffic (pending count above the watermark) followed by a disconnect. There are two teardown races to close: * rtl8xxxu_queue_rx_urb() decided whether to enqueue under rx_urb_lock but called schedule_work() after dropping the lock. A completion that observed shutdown == false and released the lock could then call schedule_work() after rtl8xxxu_stop() had set shutdown and cancel_work_sync() had already returned, arming the worker to run after the teardown. Move schedule_work() under the same !shutdown branch so the arming decision is atomic with the shutdown check. * rtl8xxxu_rx_urb_work() anchors every URB it drained back onto rx_anchor through rtl8xxxu_submit_rx_urb(). A worker still running when usb_kill_anchored_urbs(&priv->rx_anchor) returned would submit a URB that escaped the kill. In rtl8xxxu_stop(), call cancel_work_sync(&priv->rx_urb_wq) before the kill so the worker is drained first. After priv->shutdown is set under rx_urb_lock, completions can no longer queue rx_urb_wq. cancel_work_sync() then drains the last queued or running worker, and the following usb_kill_anchored_urbs() kills the URBs it may have submitted. rtl8xxxu_disconnect() is covered because ieee80211_unregister_hw() guarantees .stop() runs for a live interface before ieee80211_free_hw() frees priv. The probe error path needs no cancel: rx_urb_wq is INIT_WORK()'d there but cannot have been scheduled, since no URB is submitted before ieee80211_register_hw() succeeds. This bug was found by static analysis.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001590000 probability, percentile 0.053770000 (date 2026-09-14)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 26f1fad29ad973b0fb26a9ca3dcb2a73dde781aa 800d2b490a9af1e7132a3564c2ad5a81292e5b40 git Not specified
CNA Linux Linux affected 26f1fad29ad973b0fb26a9ca3dcb2a73dde781aa 620acb1e8037b73a457dc8ef20fc23fc7adcb405 git Not specified
CNA Linux Linux affected 26f1fad29ad973b0fb26a9ca3dcb2a73dde781aa 972ab8b9c08f3eb3fa535082de2950dd93604dfd git Not specified
CNA Linux Linux affected 26f1fad29ad973b0fb26a9ca3dcb2a73dde781aa 6c080026ecc17eecb103f8927c64ea73a74bb818 git Not specified
CNA Linux Linux affected 4.4 Not specified
CNA Linux Linux unaffected 4.4 semver Not specified
CNA Linux Linux unaffected 6.12.109 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.50 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.4 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/800d2b490a9af1e7132a3564c2ad5a81292e5b40 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/972ab8b9c08f3eb3fa535082de2950dd93604dfd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/620acb1e8037b73a457dc8ef20fc23fc7adcb405 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6c080026ecc17eecb103f8927c64ea73a74bb818 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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