FKIE_CVE-2026-63905

Vulnerability from fkie_nvd - Published: 2026-07-19 16:17 - Updated: 2026-07-19 16:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: usbip: vudc: Fix use after free bug in vudc_remove due to race condition This patch follows up Zheng Wang's 2023 report of a use-after-free in vudc_remove(). The original thread stalled on Shuah Khan's request for runtime testing of the unplug/unbind path. This patch supplies that testing and keeps Zheng's original fix shape. In vudc_probe(), v_init_timer() binds udc->tr_timer.timer to v_timer(). usbip_sockfd_store() starts the timer via v_start_timer()/v_kick_timer(). vudc_remove() can then free the containing struct vudc while the timer is still pending or executing. KASAN confirms the race on an unpatched x86_64 QEMU guest with CONFIG_KASAN=y, CONFIG_USBIP_VUDC=y, CONFIG_USB_ZERO=y, and a tight loop that repeatedly writes a socket fd to usbip_sockfd, closes the socket pair, and unbinds/rebinds usbip-vudc.0: BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x8ba/0x8e0 Write of size 8 at addr ffff888001b80740 by task trigger_and_unb/239 Allocated by task 239: vudc_probe+0x4d/0xaa0 Freed by task 239: kfree+0x18f/0x520 device_release_driver_internal+0x388/0x540 unbind_store+0xd9/0x100 This lands in the timer core rather than v_timer() itself because the embedded timer_list is being walked after its containing struct vudc has already been freed. The underlying lifetime bug is the same one Zheng reported. With v_stop_timer() called from vudc_remove() and the timer deleted synchronously, the same harness completed 5000 bind/unbind iterations with no KASAN report.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1036ac6148995feaf486014d32bf26bf993c06a9
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/207bf80362df3fce8ebc9723351dcb1bc6d9ed0f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/61704e5cf9cd7464b510eb606e7e2978b1160a64
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/88d459e5b5a46da1ef9fd6f52d9439343edeec88
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a0638db2340ee053ab0450656a763fd111475e54
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d07ed707467ce05ea9c03412d0c5ee9d0fe386a6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d96209626a29ea64666be98c30b30ac82e5f1be6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dcc1c90b28b28b7c493547506297e78653f81952
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/usbip/vudc_dev.c",
            "drivers/usb/usbip/vudc_transfer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "61704e5cf9cd7464b510eb606e7e2978b1160a64",
              "status": "affected",
              "version": "b6a0ca11186759ad7045d68a5447b1e89f658384",
              "versionType": "git"
            },
            {
              "lessThan": "dcc1c90b28b28b7c493547506297e78653f81952",
              "status": "affected",
              "version": "b6a0ca11186759ad7045d68a5447b1e89f658384",
              "versionType": "git"
            },
            {
              "lessThan": "1036ac6148995feaf486014d32bf26bf993c06a9",
              "status": "affected",
              "version": "b6a0ca11186759ad7045d68a5447b1e89f658384",
              "versionType": "git"
            },
            {
              "lessThan": "a0638db2340ee053ab0450656a763fd111475e54",
              "status": "affected",
              "version": "b6a0ca11186759ad7045d68a5447b1e89f658384",
              "versionType": "git"
            },
            {
              "lessThan": "d07ed707467ce05ea9c03412d0c5ee9d0fe386a6",
              "status": "affected",
              "version": "b6a0ca11186759ad7045d68a5447b1e89f658384",
              "versionType": "git"
            },
            {
              "lessThan": "88d459e5b5a46da1ef9fd6f52d9439343edeec88",
              "status": "affected",
              "version": "b6a0ca11186759ad7045d68a5447b1e89f658384",
              "versionType": "git"
            },
            {
              "lessThan": "207bf80362df3fce8ebc9723351dcb1bc6d9ed0f",
              "status": "affected",
              "version": "b6a0ca11186759ad7045d68a5447b1e89f658384",
              "versionType": "git"
            },
            {
              "lessThan": "d96209626a29ea64666be98c30b30ac82e5f1be6",
              "status": "affected",
              "version": "b6a0ca11186759ad7045d68a5447b1e89f658384",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/usbip/vudc_dev.c",
            "drivers/usb/usbip/vudc_transfer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.7"
            },
            {
              "lessThan": "4.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.210",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.93",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "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\nusbip: vudc: Fix use after free bug in vudc_remove due to race condition\n\nThis patch follows up Zheng Wang\u0027s 2023 report of a use-after-free in\nvudc_remove(). The original thread stalled on Shuah Khan\u0027s request for\nruntime testing of the unplug/unbind path. This patch supplies that\ntesting and keeps Zheng\u0027s original fix shape.\n\nIn vudc_probe(), v_init_timer() binds udc-\u003etr_timer.timer to v_timer().\nusbip_sockfd_store() starts the timer via v_start_timer()/v_kick_timer().\nvudc_remove() can then free the containing struct vudc while the timer is\nstill pending or executing.\n\nKASAN confirms the race on an unpatched x86_64 QEMU guest with\nCONFIG_KASAN=y, CONFIG_USBIP_VUDC=y, CONFIG_USB_ZERO=y, and a tight loop\nthat repeatedly writes a socket fd to usbip_sockfd, closes the socket\npair, and unbinds/rebinds usbip-vudc.0:\n\n  BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x8ba/0x8e0\n  Write of size 8 at addr ffff888001b80740 by task trigger_and_unb/239\n  Allocated by task 239:\n    vudc_probe+0x4d/0xaa0\n  Freed by task 239:\n    kfree+0x18f/0x520\n    device_release_driver_internal+0x388/0x540\n    unbind_store+0xd9/0x100\n\nThis lands in the timer core rather than v_timer() itself because the\nembedded timer_list is being walked after its containing struct vudc has\nalready been freed. The underlying lifetime bug is the same one Zheng\nreported.\n\nWith v_stop_timer() called from vudc_remove() and the timer deleted\nsynchronously, the same harness completed 5000 bind/unbind iterations\nwith no KASAN report."
    }
  ],
  "id": "CVE-2026-63905",
  "lastModified": "2026-07-19T16:17:08.260",
  "metrics": {},
  "published": "2026-07-19T16:17:08.260",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1036ac6148995feaf486014d32bf26bf993c06a9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/207bf80362df3fce8ebc9723351dcb1bc6d9ed0f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/61704e5cf9cd7464b510eb606e7e2978b1160a64"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/88d459e5b5a46da1ef9fd6f52d9439343edeec88"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a0638db2340ee053ab0450656a763fd111475e54"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d07ed707467ce05ea9c03412d0c5ee9d0fe386a6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d96209626a29ea64666be98c30b30ac82e5f1be6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dcc1c90b28b28b7c493547506297e78653f81952"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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