FKIE_CVE-2026-80824

Vulnerability from fkie_nvd - Published: 2026-09-04 16:18 - Updated: 2026-10-19 09:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: usb: usbfs: fix use-after-free of usb_device in usbdev_release() usbdev_release() drops its reference to the struct usb_device before draining the list of completed async URBs, but that drain path reads back through the same object: free_async() calls dec_usb_memory_use_count() for any URB whose buffer came from the usbfs mmap() region, and its first statement is bus_to_hcd(ps->dev->bus). After a disconnect the usbfs reference can be the last one, in which case usb_put_dev() frees the device and the subsequent loop reads offset 80 of freed memory and uses the result as a struct usb_hcd *, which hcd_buffer_free_pages() then dereferences. This is reachable by an unprivileged process that has read/write access to a /dev/bus/usb node: mmap() the fd, submit one URB with a buffer inside the mapping, wait for the device to be unplugged, then munmap() and close(). It reproduces on every attempt rather than being a race, because a live MAP_SHARED vma holds a reference on the struct file, so usbdev_release() cannot run until the last vma is gone and the freeing branch of dec_usb_memory_use_count() is always taken. BUG: KASAN: slab-use-after-free in dec_usb_memory_use_count+0x3ae/0x410 Read of size 8 at addr ffff8880122ee050 by task poc/769 CPU: 1 UID: 1000 PID: 769 Comm: poc Tainted: G B 6.12.94 #3 Call Trace: dec_usb_memory_use_count+0x3ae/0x410 free_async+0x2aa/0x4f0 usbdev_release+0x375/0x460 __fput+0x3ea/0xb50 __x64_sys_close+0x86/0x100 Allocated by task 11: usb_alloc_dev+0x55/0xd90 hub_event+0x2524/0x43d0 Freed by task 769: kfree+0x121/0x360 device_release+0xd2/0x280 usb_put_dev+0x23/0x30 usbdev_release+0x2d8/0x460 Release the device reference after the drain loop instead. Nothing between the two points requires it to have been dropped.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0a960b88c5979f853019d4dc4957dfbeeb193440
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0dd68b5d01d022fc9c5e71c82a82b0a94d3d0671
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/47a7f98fbb5006d46d15a3a210ffdc61448a4f19
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5f08c45bdcfd28d1171de38c5ef29fc89a76eedc
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/65879e0a452ca2a234b9475e0c11aff7a4343738
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7f0278e474c4d1c4457974ff1137cc385c944ab3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/96f5520fc9a5e4bbf77ac93c9d5ce502f597e6cf
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b3cde26a66b04f1d90ed0b675899c88b4e49d424
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bd4bffc621a8cb2f4d9ed9b6447415de524a3bef
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/core/devio.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0a960b88c5979f853019d4dc4957dfbeeb193440",
              "status": "affected",
              "version": "f7d34b445abc00e979b7cf36b9580ac3d1a47cd8",
              "versionType": "git"
            },
            {
              "lessThan": "96f5520fc9a5e4bbf77ac93c9d5ce502f597e6cf",
              "status": "affected",
              "version": "f7d34b445abc00e979b7cf36b9580ac3d1a47cd8",
              "versionType": "git"
            },
            {
              "lessThan": "bd4bffc621a8cb2f4d9ed9b6447415de524a3bef",
              "status": "affected",
              "version": "f7d34b445abc00e979b7cf36b9580ac3d1a47cd8",
              "versionType": "git"
            },
            {
              "lessThan": "65879e0a452ca2a234b9475e0c11aff7a4343738",
              "status": "affected",
              "version": "f7d34b445abc00e979b7cf36b9580ac3d1a47cd8",
              "versionType": "git"
            },
            {
              "lessThan": "b3cde26a66b04f1d90ed0b675899c88b4e49d424",
              "status": "affected",
              "version": "f7d34b445abc00e979b7cf36b9580ac3d1a47cd8",
              "versionType": "git"
            },
            {
              "lessThan": "5f08c45bdcfd28d1171de38c5ef29fc89a76eedc",
              "status": "affected",
              "version": "f7d34b445abc00e979b7cf36b9580ac3d1a47cd8",
              "versionType": "git"
            },
            {
              "lessThan": "7f0278e474c4d1c4457974ff1137cc385c944ab3",
              "status": "affected",
              "version": "f7d34b445abc00e979b7cf36b9580ac3d1a47cd8",
              "versionType": "git"
            },
            {
              "lessThan": "47a7f98fbb5006d46d15a3a210ffdc61448a4f19",
              "status": "affected",
              "version": "f7d34b445abc00e979b7cf36b9580ac3d1a47cd8",
              "versionType": "git"
            },
            {
              "lessThan": "0dd68b5d01d022fc9c5e71c82a82b0a94d3d0671",
              "status": "affected",
              "version": "f7d34b445abc00e979b7cf36b9580ac3d1a47cd8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/core/devio.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.6"
            },
            {
              "lessThan": "4.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.269",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.220",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.187",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.156",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.108",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.49",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: usbfs: fix use-after-free of usb_device in usbdev_release()\n\nusbdev_release() drops its reference to the struct usb_device before\ndraining the list of completed async URBs, but that drain path reads back\nthrough the same object: free_async() calls dec_usb_memory_use_count()\nfor any URB whose buffer came from the usbfs mmap() region, and its first\nstatement is bus_to_hcd(ps-\u003edev-\u003ebus).\n\nAfter a disconnect the usbfs reference can be the last one, in which case\nusb_put_dev() frees the device and the subsequent loop reads offset 80 of\nfreed memory and uses the result as a struct usb_hcd *, which\nhcd_buffer_free_pages() then dereferences.\n\nThis is reachable by an unprivileged process that has read/write access to\na /dev/bus/usb node: mmap() the fd, submit one URB with a buffer inside the\nmapping, wait for the device to be unplugged, then munmap() and close().\nIt reproduces on every attempt rather than being a race, because a live\nMAP_SHARED vma holds a reference on the struct file, so usbdev_release()\ncannot run until the last vma is gone and the freeing branch of\ndec_usb_memory_use_count() is always taken.\n\n  BUG: KASAN: slab-use-after-free in dec_usb_memory_use_count+0x3ae/0x410\n  Read of size 8 at addr ffff8880122ee050 by task poc/769\n  CPU: 1 UID: 1000 PID: 769 Comm: poc Tainted: G    B    6.12.94 #3\n\n  Call Trace:\n   dec_usb_memory_use_count+0x3ae/0x410\n   free_async+0x2aa/0x4f0\n   usbdev_release+0x375/0x460\n   __fput+0x3ea/0xb50\n   __x64_sys_close+0x86/0x100\n\n  Allocated by task 11:\n   usb_alloc_dev+0x55/0xd90\n   hub_event+0x2524/0x43d0\n\n  Freed by task 769:\n   kfree+0x121/0x360\n   device_release+0xd2/0x280\n   usb_put_dev+0x23/0x30\n   usbdev_release+0x2d8/0x460\n\nRelease the device reference after the drain loop instead. Nothing between\nthe two points requires it to have been dropped."
    }
  ],
  "id": "CVE-2026-80824",
  "lastModified": "2026-10-19T09:17:17.293",
  "metrics": {},
  "published": "2026-09-04T16:18:10.233",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0a960b88c5979f853019d4dc4957dfbeeb193440"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0dd68b5d01d022fc9c5e71c82a82b0a94d3d0671"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/47a7f98fbb5006d46d15a3a210ffdc61448a4f19"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5f08c45bdcfd28d1171de38c5ef29fc89a76eedc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/65879e0a452ca2a234b9475e0c11aff7a4343738"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7f0278e474c4d1c4457974ff1137cc385c944ab3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/96f5520fc9a5e4bbf77ac93c9d5ce502f597e6cf"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b3cde26a66b04f1d90ed0b675899c88b4e49d424"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bd4bffc621a8cb2f4d9ed9b6447415de524a3bef"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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