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usbnet: Fix linkwatch use-after-free on disconnect

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: usbnet: Fix linkwatch use-after-free on disconnect usbnet uses the work usbnet_deferred_kevent() to perform tasks which may sleep. On disconnect, completion of the work was originally awaited in ->ndo_stop(). But in 2003, that was moved to ->disconnect() by historic commit "[PATCH] USB: usbnet, prevent exotic rtnl deadlock": https://git.kernel.org/tglx/history/c/0f138bbfd83c The change was made because back then, the kernel's workqueue implementation did not allow waiting for a single work. One had to wait for completion of *all* work by calling flush_scheduled_work(), and that could deadlock when waiting for usbnet_deferred_kevent() with rtnl_mutex held in ->ndo_stop(). The commit solved one problem but created another: It causes a use-after-free in USB Ethernet drivers aqc111.c, asix_devices.c, ax88179_178a.c, ch9200.c and smsc75xx.c: * If the drivers receive a link change interrupt immediately before disconnect, they raise EVENT_LINK_RESET in their (non-sleepable) ->status() callback and schedule usbnet_deferred_kevent(). * usbnet_deferred_kevent() invokes the driver's ->link_reset() callback, which calls netif_carrier_{on,off}(). * That in turn schedules the work linkwatch_event(). Because usbnet_deferred_kevent() is awaited after unregister_netdev(), netif_carrier_{on,off}() may operate on an unregistered netdev and linkwatch_event() may run after free_netdev(), causing a use-after-free. In 2010, usbnet

Products
Kernel
Affected versions
Not specified
Fixed versions
4.14.291, 4.19.256, 4.9.326, 5.10.137, 5.15.61, 5.18.18, 5.19.2, 5.4.211
CVEs
CVE-2022-50220
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 00:44 UTC · Revision 1

Source evidence

usbnet: Fix linkwatch use-after-free on disconnect

core-osv · Original source

Published 18 Jun 2025, 11:03 UTC

In the Linux kernel, the following vulnerability has been resolved: usbnet: Fix linkwatch use-after-free on disconnect usbnet uses the work usbnet_deferred_kevent() to perform tasks which may sleep. On disconnect, completion of the work was originally awaited in ->ndo_stop(). But in 2003, that was moved to ->disconnect() by historic commit "[PATCH] USB: usbnet, prevent exotic rtnl deadlock": https://git.kernel.org/tglx/history/c/0f138bbfd83c The change was made because back then, the kernel's workqueue implementation did not allow waiting for a single work. One had to wait for completion of *all* work by calling flush_scheduled_work(), and that could deadlock when waiting for usbnet_deferred_kevent() with rtnl_mutex held in ->ndo_stop(). The commit solved one problem but created another: It causes a use-after-free in USB Ethernet drivers aqc111.c, asix_devices.c, ax88179_178a.c, ch9200.c and smsc75xx.c: * If the drivers receive a link change interrupt immediately before disconnect, they raise EVENT_LINK_RESET in their (non-sleepable) ->status() callback and schedule usbnet_deferred_kevent(). * usbnet_deferred_kevent() invokes the driver's ->link_reset() callback, which calls netif_carrier_{on,off}(). * That in turn schedules the work linkwatch_event(). Because usbnet_deferred_kevent() is awaited after unregister_netdev(), netif_carrier_{on,off}() may operate on an unregistered netdev and linkwatch_event() may run after free_netdev(), causing a use-after-free. In 2010, usbnet

osv:CVE-2022-50220

Kernel

Fixed versions: 4.9.326, 4.14.291, 4.19.256, 5.4.211, 5.10.137, 5.15.61, 5.18.18, 5.19.2

Complete source record
{
  "id": "63367b050ec949937cfc11279c1713f313f2c00f055c917e284084bd077ca3e9",
  "url": "https://osv.dev/vulnerability/CVE-2022-50220",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "usbnet: Fix linkwatch use-after-free on disconnect",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: usbnet: Fix linkwatch use-after-free on disconnect usbnet uses the work usbnet_deferred_kevent() to perform tasks which may sleep. On disconnect, completion of the work was originally awaited in ->ndo_stop(). But in 2003, that was moved to ->disconnect() by historic commit \"[PATCH] USB: usbnet, prevent exotic rtnl deadlock\": https://git.kernel.org/tglx/history/c/0f138bbfd83c The change was made because back then, the kernel's workqueue implementation did not allow waiting for a single work. One had to wait for completion of *all* work by calling flush_scheduled_work(), and that could deadlock when waiting for usbnet_deferred_kevent() with rtnl_mutex held in ->ndo_stop(). The commit solved one problem but created another: It causes a use-after-free in USB Ethernet drivers aqc111.c, asix_devices.c, ax88179_178a.c, ch9200.c and smsc75xx.c: * If the drivers receive a link change interrupt immediately before disconnect, they raise EVENT_LINK_RESET in their (non-sleepable) ->status() callback and schedule usbnet_deferred_kevent(). * usbnet_deferred_kevent() invokes the driver's ->link_reset() callback, which calls netif_carrier_{on,off}(). * That in turn schedules the work linkwatch_event(). Because usbnet_deferred_kevent() is awaited after unregister_netdev(), netif_carrier_{on,off}() may operate on an unregistered netdev and linkwatch_event() may run after free_netdev(), causing a use-after-free. In 2010, usbnet ",
    "evidence": "osv:CVE-2022-50220",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.9.326",
            "evidence": "/affected/1/ranges"
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            "value": "4.14.291",
            "evidence": "/affected/1/ranges"
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          {
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            "evidence": "/affected/1/ranges"
          },
          {
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            "evidence": "/affected/1/ranges"
          },
          {
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            "evidence": "/affected/1/ranges"
          },
          {
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            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.18.18",
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          },
          {
            "value": "5.19.2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2022-50220",
      "aliases": [
        "CVE-2022-50220"
      ],
      "affected": [
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50220.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
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                {
                  "introduced": "2.6.38"
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            {
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            {
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                {
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            },
            {
              "type": "ECOSYSTEM",
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
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      ],
      "modified": "2026-10-28T02:30:24.928848476Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/135199a2edd459d2b123144efcd7f9bcd95128e4",
        "https://git.kernel.org/stable/c/635fd8953e4309b54ca6a81bed1d4a87668694f4",
        "https://git.kernel.org/stable/c/7f77dcbc030c2faa6d8e8a594985eeb34018409e",
        "https://git.kernel.org/stable/c/8b4588b8b00b299be16a35be67b331d8fdba03f3",
        "https://git.kernel.org/stable/c/a69e617e533edddf3fa3123149900f36e0a6dc74",
        "https://git.kernel.org/stable/c/d2d6b530d89b0a912148018027386aa049f0a309",
        "https://git.kernel.org/stable/c/d49bb8cf9bfaa06aa527eb30f1a52a071da2e32f",
        "https://git.kernel.org/stable/c/db3b738ae5f726204876f4303c49cfdf4311403f",
        "https://git.kernel.org/stable/c/e2a521a7dcc463c5017b4426ca0804e151faeff7",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50220.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2022-50220",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50220.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2022-50220",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 491286,
  "published_at": "2025-06-18T11:03:55.461+00:00"
}