Description
In 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.
Published: 2026-09-11
Score: 7.1 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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History

Sat, 12 Sep 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-825
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important


Fri, 11 Sep 2026 23:45:00 +0000

Type Values Removed Values Added
Description In 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.
Title wifi: rtl8xxxu: fix use-after-free from rx_urb_wq on stop
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-11T19:42:18.282Z

Reserved: 2026-08-26T14:34:25.803Z

Link: CVE-2026-80947

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-11T20:19:00.303

Modified: 2026-09-11T20:19:00.303

Link: CVE-2026-80947

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-11T19:42:18Z

Links: CVE-2026-80947 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-825

    Expired Pointer Dereference