CVE-2026-80947 (GCVE-0-2026-80947)
Vulnerability from cvelistv5
Published
2026-09-11 19:42
Modified
2026-10-21 12:47
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: 26f1fad29ad973b0fb26a9ca3dcb2a73dde781aa
Version: 26f1fad29ad973b0fb26a9ca3dcb2a73dde781aa
Version: 26f1fad29ad973b0fb26a9ca3dcb2a73dde781aa
Version: 26f1fad29ad973b0fb26a9ca3dcb2a73dde781aa
Version: 26f1fad29ad973b0fb26a9ca3dcb2a73dde781aa
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/wireless/realtek/rtl8xxxu/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/wireless/realtek/rtl8xxxu/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.4"
            },
            {
              "lessThan": "4.4",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
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            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.160",
                  "versionStartIncluding": "4.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.109",
                  "versionStartIncluding": "4.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
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                },
                {
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: rtl8xxxu: fix use-after-free from rx_urb_wq on stop\n\nrtl8xxxu arms rx_urb_wq from the RX completion path:\nrtl8xxxu_rx_complete() hands the URB to rtl8xxxu_queue_rx_urb(), which\nqueues it on rx_urb_pending_list and, once the list grows past\nRTL8XXXU_RX_URB_PENDING_WATER, schedules rx_urb_wq.  The worker\nrtl8xxxu_rx_urb_work() drains rx_urb_pending_list, recovers priv through\ncontainer_of, and resubmits each URB through rtl8xxxu_submit_rx_urb(),\nwhich anchors it on rx_anchor and dereferences priv-\u003eudev.\n\nrtl8xxxu_stop() cancels the sibling work items (c2hcmd_work, ra_watchdog,\nupdate_beacon_work) but never cancels rx_urb_wq, so a worker armed during\nthe last burst of RX traffic can run rtl8xxxu_rx_urb_work() after\nrtl8xxxu_disconnect() has called ieee80211_free_hw(), which frees priv,\nproducing a use-after-free.  The window opens under active RX traffic\n(pending count above the watermark) followed by a disconnect.\n\nThere are two teardown races to close:\n\n  * rtl8xxxu_queue_rx_urb() decided whether to enqueue under rx_urb_lock\n    but called schedule_work() after dropping the lock.  A completion\n    that observed shutdown == false and released the lock could then call\n    schedule_work() after rtl8xxxu_stop() had set shutdown and\n    cancel_work_sync() had already returned, arming the worker to run\n    after the teardown.  Move schedule_work() under the same !shutdown\n    branch so the arming decision is atomic with the shutdown check.\n\n  * rtl8xxxu_rx_urb_work() anchors every URB it drained back onto\n    rx_anchor through rtl8xxxu_submit_rx_urb().  A worker still running\n    when usb_kill_anchored_urbs(\u0026priv-\u003erx_anchor) returned would submit a\n    URB that escaped the kill.  In rtl8xxxu_stop(), call\n    cancel_work_sync(\u0026priv-\u003erx_urb_wq) before the kill so the worker is\n    drained first.\n\nAfter priv-\u003eshutdown is set under rx_urb_lock, completions can no longer\nqueue rx_urb_wq. cancel_work_sync() then drains the last queued or running\nworker, and the following usb_kill_anchored_urbs() kills the URBs it may\nhave submitted.\n\nrtl8xxxu_disconnect() is covered because ieee80211_unregister_hw()\nguarantees .stop() runs for a live interface before ieee80211_free_hw()\nfrees priv.  The probe error path needs no cancel: rx_urb_wq is\nINIT_WORK()\u0027d there but cannot have been scheduled, since no URB is\nsubmitted before ieee80211_register_hw() succeeds.\n\nThis bug was found by static analysis."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is reached when rtl8xxxu_stop()/rtl8xxxu_disconnect() runs while rx_urb_wq is armed. An adjacent Wi-Fi peer can complete RX URBs and queue the work, but cannot invoke stop or ieee80211_free_hw(); teardown is a local action (interface down, rfkill, suspend, USB unbind or unplug).\nAC:L - The attacker controls both sides of the race: they generate RX traffic so rx_urb_pending_count exceeds RTL8XXXU_RX_URB_PENDING_WATER (8) and schedule_work(\u0026rx_urb_wq) fires, then they trigger stop/disconnect while the worker is queued or still resubmitting URBs, retrying until the window after ieee80211_free_hw() is hit.\nPR:L - An ordinary local user can trigger teardown via logind-mediated suspend, rfkill, or USB unplug on a shared workstation, and needs no capability to generate the RX traffic that queues rx_urb_wq. CAP_NET_ADMIN to bring the interface down is also available via user namespaces when the wiphy is delegated into that netns.\nUI:N - The attacker generates the RX burst and performs the interface stop or USB disconnect themselves; no separate victim must open a file, mount a filesystem, or otherwise interact.\nS:U - The use-after-free corrupts the rtl8xxxu_priv kernel object and USB URB state inside the host kernel; it does not cross a VM, IOMMU, or sandbox boundary.\nC:H - rtl8xxxu_rx_urb_work() recovers the freed priv via container_of and reads priv-\u003eudev, priv-\u003efops, and pending-list/rx_anchor state. A sprayed replacement slab object therefore yields an arbitrary kernel read primitive.\nI:H - The worker list_splice_init()s the freed pending list, usb_anchor_urb()s onto priv-\u003erx_anchor, and the workqueue core mutates the embedded work_struct inside the freed priv, giving heap-write and control-flow hijack primitives.\nA:H - Executing rtl8xxxu_rx_urb_work() against freed priv oopses or panics on the spinlock, list, or udev dereference, and the attacker can retrigger it on every device stop or USB disconnect."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:47:17.715Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/17d5ae58973122eea7625a87cd3d80a8beb23b47"
        },
        {
          "url": "https://git.kernel.org/stable/c/800d2b490a9af1e7132a3564c2ad5a81292e5b40"
        },
        {
          "url": "https://git.kernel.org/stable/c/620acb1e8037b73a457dc8ef20fc23fc7adcb405"
        },
        {
          "url": "https://git.kernel.org/stable/c/972ab8b9c08f3eb3fa535082de2950dd93604dfd"
        },
        {
          "url": "https://git.kernel.org/stable/c/6c080026ecc17eecb103f8927c64ea73a74bb818"
        }
      ],
      "title": "wifi: rtl8xxxu: fix use-after-free from rx_urb_wq on stop",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80947",
    "datePublished": "2026-09-11T19:42:18.282Z",
    "dateReserved": "2026-08-26T14:34:25.803Z",
    "dateUpdated": "2026-10-21T12:47:17.715Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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