GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

FKIE_CVE-2026-80824

Vulnerability from fkie_nvd - Published: 2026-09-04 16:18 - Updated: 2026-09-04 16:18
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
To clipboard 

{
  "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-rc1",
              "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": "2026-09-04T16:18:10.233",
  "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"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.