CVE-2026-23320 (GCVE-0-2026-23320)

Vulnerability from cvelistv5 – Published: 2026-03-25 10:27 – Updated: 2026-03-25 10:27
VLAI?
Title
usb: gadget: f_ncm: align net_device lifecycle with bind/unbind
Summary
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_ncm: align net_device lifecycle with bind/unbind Currently, the net_device is allocated in ncm_alloc_inst() and freed in ncm_free_inst(). This ties the network interface's lifetime to the configuration instance rather than the USB connection (bind/unbind). This decoupling causes issues when the USB gadget is disconnected where the underlying gadget device is removed. The net_device can outlive its parent, leading to dangling sysfs links and NULL pointer dereferences when accessing the freed gadget device. Problem 1: NULL pointer dereference on disconnect Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Call trace: __pi_strlen+0x14/0x150 rtnl_fill_ifinfo+0x6b4/0x708 rtmsg_ifinfo_build_skb+0xd8/0x13c rtmsg_ifinfo+0x50/0xa0 __dev_notify_flags+0x4c/0x1f0 dev_change_flags+0x54/0x70 do_setlink+0x390/0xebc rtnl_newlink+0x7d0/0xac8 rtnetlink_rcv_msg+0x27c/0x410 netlink_rcv_skb+0x134/0x150 rtnetlink_rcv+0x18/0x28 netlink_unicast+0x254/0x3f0 netlink_sendmsg+0x2e0/0x3d4 Problem 2: Dangling sysfs symlinks console:/ # ls -l /sys/class/net/ncm0 lrwxrwxrwx ... /sys/class/net/ncm0 -> /sys/devices/platform/.../gadget.0/net/ncm0 console:/ # ls -l /sys/devices/platform/.../gadget.0/net/ncm0 ls: .../gadget.0/net/ncm0: No such file or directory Move the net_device allocation to ncm_bind() and deallocation to ncm_unbind(). This ensures the network interface exists only when the gadget function is actually bound to a configuration. To support pre-bind configuration (e.g., setting interface name or MAC address via configfs), cache user-provided options in f_ncm_opts using the gether_opts structure. Apply these cached settings to the net_device upon creation in ncm_bind(). Preserve the use-after-free fix from commit 6334b8e4553c ("usb: gadget: f_ncm: Fix UAF ncm object at re-bind after usb ep transport error"). Check opts->net in ncm_set_alt() and ncm_disable() to ensure gether_disconnect() runs only if a connection was established.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 40d133d7f542616cf9538508a372306e626a16e9 , < b62076e780a2121903ecf9ffdfb89c64647cb7da (git)
Affected: 40d133d7f542616cf9538508a372306e626a16e9 , < 188338c1827842f898761a939669cf345bdf07e2 (git)
Affected: 40d133d7f542616cf9538508a372306e626a16e9 , < 56a512a9b4107079f68701e7d55da8507eb963d9 (git)
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    Linux Linux Affected: 3.11
Unaffected: 0 , < 3.11 (semver)
Unaffected: 6.18.17 , ≤ 6.18.* (semver)
Unaffected: 6.19.7 , ≤ 6.19.* (semver)
Unaffected: 7.0-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_ncm.c",
            "drivers/usb/gadget/function/u_ncm.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "3.11"
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              "version": "6.19.7",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.0-rc1",
              "versionType": "original_commit_for_fix"
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                  "vulnerable": true
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                {
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                  "versionEndExcluding": "6.19.7",
                  "versionStartIncluding": "3.11",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0-rc1",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_ncm: align net_device lifecycle with bind/unbind\n\nCurrently, the net_device is allocated in ncm_alloc_inst() and freed in\nncm_free_inst(). This ties the network interface\u0027s lifetime to the\nconfiguration instance rather than the USB connection (bind/unbind).\n\nThis decoupling causes issues when the USB gadget is disconnected where\nthe underlying gadget device is removed. The net_device can outlive its\nparent, leading to dangling sysfs links and NULL pointer dereferences\nwhen accessing the freed gadget device.\n\nProblem 1: NULL pointer dereference on disconnect\n Unable to handle kernel NULL pointer dereference at virtual address\n 0000000000000000\n Call trace:\n   __pi_strlen+0x14/0x150\n   rtnl_fill_ifinfo+0x6b4/0x708\n   rtmsg_ifinfo_build_skb+0xd8/0x13c\n   rtmsg_ifinfo+0x50/0xa0\n   __dev_notify_flags+0x4c/0x1f0\n   dev_change_flags+0x54/0x70\n   do_setlink+0x390/0xebc\n   rtnl_newlink+0x7d0/0xac8\n   rtnetlink_rcv_msg+0x27c/0x410\n   netlink_rcv_skb+0x134/0x150\n   rtnetlink_rcv+0x18/0x28\n   netlink_unicast+0x254/0x3f0\n   netlink_sendmsg+0x2e0/0x3d4\n\nProblem 2: Dangling sysfs symlinks\n console:/ # ls -l /sys/class/net/ncm0\n lrwxrwxrwx ... /sys/class/net/ncm0 -\u003e\n /sys/devices/platform/.../gadget.0/net/ncm0\n console:/ # ls -l /sys/devices/platform/.../gadget.0/net/ncm0\n ls: .../gadget.0/net/ncm0: No such file or directory\n\nMove the net_device allocation to ncm_bind() and deallocation to\nncm_unbind(). This ensures the network interface exists only when the\ngadget function is actually bound to a configuration.\n\nTo support pre-bind configuration (e.g., setting interface name or MAC\naddress via configfs), cache user-provided options in f_ncm_opts\nusing the gether_opts structure. Apply these cached settings to the\nnet_device upon creation in ncm_bind().\n\nPreserve the use-after-free fix from commit 6334b8e4553c (\"usb: gadget:\nf_ncm: Fix UAF ncm object at re-bind after usb ep transport error\").\nCheck opts-\u003enet in ncm_set_alt() and ncm_disable() to ensure\ngether_disconnect() runs only if a connection was established."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-25T10:27:14.398Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b62076e780a2121903ecf9ffdfb89c64647cb7da"
        },
        {
          "url": "https://git.kernel.org/stable/c/188338c1827842f898761a939669cf345bdf07e2"
        },
        {
          "url": "https://git.kernel.org/stable/c/56a512a9b4107079f68701e7d55da8507eb963d9"
        }
      ],
      "title": "usb: gadget: f_ncm: align net_device lifecycle with bind/unbind",
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        "engine": "bippy-1.2.0"
      }
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23320",
    "datePublished": "2026-03-25T10:27:14.398Z",
    "dateReserved": "2026-01-13T15:37:45.995Z",
    "dateUpdated": "2026-03-25T10:27:14.398Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-23320\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-03-25T11:16:28.747\",\"lastModified\":\"2026-03-25T15:41:33.977\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nusb: gadget: f_ncm: align net_device lifecycle with bind/unbind\\n\\nCurrently, the net_device is allocated in ncm_alloc_inst() and freed in\\nncm_free_inst(). This ties the network interface\u0027s lifetime to the\\nconfiguration instance rather than the USB connection (bind/unbind).\\n\\nThis decoupling causes issues when the USB gadget is disconnected where\\nthe underlying gadget device is removed. The net_device can outlive its\\nparent, leading to dangling sysfs links and NULL pointer dereferences\\nwhen accessing the freed gadget device.\\n\\nProblem 1: NULL pointer dereference on disconnect\\n Unable to handle kernel NULL pointer dereference at virtual address\\n 0000000000000000\\n Call trace:\\n   __pi_strlen+0x14/0x150\\n   rtnl_fill_ifinfo+0x6b4/0x708\\n   rtmsg_ifinfo_build_skb+0xd8/0x13c\\n   rtmsg_ifinfo+0x50/0xa0\\n   __dev_notify_flags+0x4c/0x1f0\\n   dev_change_flags+0x54/0x70\\n   do_setlink+0x390/0xebc\\n   rtnl_newlink+0x7d0/0xac8\\n   rtnetlink_rcv_msg+0x27c/0x410\\n   netlink_rcv_skb+0x134/0x150\\n   rtnetlink_rcv+0x18/0x28\\n   netlink_unicast+0x254/0x3f0\\n   netlink_sendmsg+0x2e0/0x3d4\\n\\nProblem 2: Dangling sysfs symlinks\\n console:/ # ls -l /sys/class/net/ncm0\\n lrwxrwxrwx ... /sys/class/net/ncm0 -\u003e\\n /sys/devices/platform/.../gadget.0/net/ncm0\\n console:/ # ls -l /sys/devices/platform/.../gadget.0/net/ncm0\\n ls: .../gadget.0/net/ncm0: No such file or directory\\n\\nMove the net_device allocation to ncm_bind() and deallocation to\\nncm_unbind(). This ensures the network interface exists only when the\\ngadget function is actually bound to a configuration.\\n\\nTo support pre-bind configuration (e.g., setting interface name or MAC\\naddress via configfs), cache user-provided options in f_ncm_opts\\nusing the gether_opts structure. Apply these cached settings to the\\nnet_device upon creation in ncm_bind().\\n\\nPreserve the use-after-free fix from commit 6334b8e4553c (\\\"usb: gadget:\\nf_ncm: Fix UAF ncm object at re-bind after usb ep transport error\\\").\\nCheck opts-\u003enet in ncm_set_alt() and ncm_disable() to ensure\\ngether_disconnect() runs only if a connection was established.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/188338c1827842f898761a939669cf345bdf07e2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/56a512a9b4107079f68701e7d55da8507eb963d9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b62076e780a2121903ecf9ffdfb89c64647cb7da\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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